draft: primary care physician and physician assistant

The Regional Center for Health Workforce Studies

at the Center for Health Economics and Policy

Changes in the Supply and Distribution of Primary Care Physicians Within Market-Defined Areas and Counties

of Texas: 1990 to 2000

Sponsored by Bureau of Health Professions

Health Resources and Services Administration U. S. Department of Health and Human Services

Under Cooperative Agreement No. U79HP00001-05

Michael L. Parchman, M.D., M.P.H. Stephen K. Blanchard, Ph.D.

Robert C. Wood, M.P.H. Antonio Furino, Ph.D.

Fall, 2005

The University of Texas Health Science Center at San Antonio

TABLE OF CONTENTS Page

List of Tables …………………………………………………………………….. ii

List of Figures ……………………………………………………………………. iii

List of County-Level Tables …………………………………………………….. iv

Preface ……………………………………………………………………………. 1

Executive Summary……………………………………………………………… 2

Background………………………………………………………………………. 5

Methods…………………………………………………………………………… 9

Results…………………………………………………………………………….. 11

Physician Supply…………………………………………………………………. 12

Primary Care Physician Supply and Distribution by PCSA………........................ 13

A Comparison of PCSA PCP Supply to Shortage Area Designations…………… 17

Primary Care Providers and Children…………………………………………….. 20

Primary Care Providers and the Elderly………………………………………….. 22

Obstetricians by PCSA…………………………………........................................ 24

Primary Care Providers and Hispanics…………………………………................ 25

The Border Region……………………………………………………………….. 27

Rural/Urban Distribution of PCPs………………………………………………... 29

Primary Care Provider Work Effort……………………………………………… 31

Stability of PCP Workforce in Texas…………………………………………….. 33

Physician Assistants……………………………………………………………… 34

Comparison of PCSA Analysis to County-Level Analysis………………………. 35

Discussion……………………………………………………………………....… 36

Future Research………………………………………………………………….. 40

Appendix 1………………………………………………………………………... 41

Changes in the Supply and Distribution of PCPs Fall 2005 Page i

List of Tables Table Title Page

1 Demographic Characteristics of Primary Care Service Areas…….. 11

2 Number of Physicians in Texas: 1990 to 2000……………………. 12

3 Primary Care Physicians per Population by PCSA: 1990 and 2000... 13

4 Pediatric Providers per 100,000 Less Than Ages 15 and 18 by PCSA: 1990 and 2000……………………………………………

20

5 Primary Care Providers per 100,000 Age 65 and Over by PCSA: 1990 and 2000……………………………………………………...

22

6 Ob/Gyn Providers per 100,000 Females by PCSA: 1990 and 2000... 24

7 Primary Care Providers per 100,000 Hispanics by PCSA: 1990 and 2000……………………………………………………………

25

8 Dependency Ratios and Demographics: 1990 and 2000…………. 28

9 Border and Non-Border PCSAs…………………………………… 28

10 Rural/Urban PCP/100,000 Comparisons…………………………... 29

11 Percent Time Spent in Direct Patient Care………………………… 31

12 Percent in Direct Patient Care More Than 40 Hours Per Week…… 31

13 County-Level versus PCSA-Level Comparison…………………... 35

Changes in the Supply and Distribution of PCPs Fall 2005 Page ii

List of Figures Figure Title Page

1 Primary Care Service Areas with County Boundary Outline Overlay……………………………………………………………..

7

2 Primary Care Physicians per 100,000 Population: 2000…………... 15

3 Change in Primary Care Physician per Population: 1990 to 2000… 16

4 Primary Care HPSA: Overlay of PCSAs with more than 3,000 People per Primary Care Physician………………………………...

18

5 Houston Partial-County HPSA: Overlay of PCSAs with more than 3,000 People per Primary Care Physician………………………….

19

6 Dallas-Fort Worth Partial-County HPSA: Overlay of PCSAs with

more than 3,000 People per Primary Care Physician………………

19

7 Pediatric Primary Care Providers per 100,000 Age Less than 18…. 21

8 Change in Pediatric Primary Care Providers per 100,000 Age Less than 18: 1990 to 2000………………………………………………

21

9 Primary Care Physicians per 100,000 Age 65 or Over: 2000…… 23

10 Change in Primary Care Physicians per 100,000 Age 65 or Over: 1990 to 2000………………………………………………………..

23

11 Number of Obstetricians in each PCSA: 2000.................................. 24

12 Primary Care Physicians per 100,000 Hispanics: 2000…………… 26

13 Change in Primary Care Providers per 100,000 Hispanics: 1990 to 2000………………………………………………………………...

26

14 Percent in Direct Patient Care 40 or more Hours per Week………. 32

15 Instability of PCPs: 1990 to 2000…………………………………. 33

16 Number of Physician Assistants within each PCSA: 2000………... 34

Appendix 1 List of County-Level Tables

Changes in the Supply and Distribution of PCPs Fall 2005 Page iii

Table Title Page

1 Primary Care Physicians per Population by County: 1990 and 2000 ………………………………………………………………..

41

2 Pediatric Providers per 100,000 Less Than Age 18 by County: 1990 and 2000 ……………………………………………………..

41

3 Primary Care Providers per 100,000 Age 65 and Over by County: 1990 and 2000 ……………………………………………………..

42

4 Ob/Gyn Providers per 100,000 Females by County: 1990 and 2000 ………………………………………………………………..

42

5 Primary Care Providers per 100,000 Hispanics by County: 1990 and 2000 …………………………………………………………...

42

6 Border and Non-Border Counties ………………………………… 43

7 Rural/Urban PCP/100,000 Comparisons ………………………….. 44

Changes in the Supply and Distribution of PCPs Fall 2005 Page iv

Preface and Acknowledgments

This report describes the research that preceded Assessing Health-Workforce Disparities in the U.S./Mexico Border Region: A Geographic Information Systems Approach, a larger work reporting on the use of GIS techniques to develop adequate tools for public administrators charged with defining health workforce shortage areas. The aim of the research reported here has been that of assessing changes in the distribution of primary care physicians and non-physician clinicians in Border and rural areas of Texas using the newly developed definitions of Primary Care Service Areas (PCSAs). The use of PCSA geography was employed, as opposed to more-traditional, politically configured county boundaries, to produce findings that reflected actual health-service areas rather than administrative conventions. The findings from this research project provided insights to the methodological and data- collection challenges facing policy makers and researchers alike. They suggest that further analyses are needed to inform policy that addresses physician-shortage areas. The study is the result of ongoing research by the Regional Center for Health Workforce Studies at CHEP. It was conducted under a cooperative agreement (HRSA-U79HP00001-05) with the Bureau of Health Professions (BHPr) at the Health Resources and Services Administration (HRSA/DHHS). The generous and skillful assistance of HRSA project officers Jim Cultice, Operation Research Analyst, and Sarah Richards, Team Leader, Regional Centers for Health Workforce Studies of the Office of Workforce Evaluation and Quality Assurance (OWEQA), is gratefully acknowledged.

Changes in the Supply and Distribution of PCPs Fall 2005 Page 1

Executive Summary

This research utilizes data on population and primary care physicians and physician assistants within PCSA boundaries in order to assess changes in the primary health-care provider workforce for certain vulnerable populations, including children, women, the elderly, Hispanics and those in Border and rural areas. While not the initial purpose of the research, a comparative analysis and preliminary exploration of the differences in measuring workforce changes using market-defined versus politically defined boundaries has been included. Changes in practice location over the decade for physician assistants (PAs) were charted for PCSAs to underscore the importance of including the non-physician clinician workforce in future research. The analysis of PCSA and county physician distributions and their changes from 1990 to 2000 relies principally upon two analytic methodologies: first, the traditional enumeration of aggregate information, and second, the calculation of means and variances from geographic entities that, instead of being summed in the aggregate, become the units of measurement for the statistical parameters. Workforce studies are typically enumerations of the counts and proportions of providers, with very little examination of the variability within and between the geographic regions of interest. This work is an attempt to explore the workforce distribution in Primary Care Service Areas employing aggregate counts and proportions, as well as the use of distribution-based statistical techniques for the comparisons of regional workforce distributions. Key Findings

1. Measuring changes in the health workforce within regions described by market- defined, as opposed to administratively configured, boundaries often produces very similar results. Some differences in the results for the distribution of primary care physicians in Texas between county- and PCSA-based geographic boundary systems were expected. This was true for selected measures of overall physician levels as well as for changes over time. However, it was not anticipated that in some cases the results for PCSAs would be apparently less sensitive to certain regional differences such as Border versus non-Border than those obtained for counties. Preliminary exploratory analysis reveals that these differences may in part be due to the fundamentally adaptive nature of geographic areas derived from using physician/patient encounter information.

2. An example of county/PCSA differences is illustrated by the following: The within-

and between-year differences in the ratios of primary care physicians per 100,000 population for the Border and non-Border regions are smaller for PCSAs than for counties. Both boundary systems show lower ratios for the Border as opposed to the non-Border regions, and both demonstrate similar changes from 1990 to 2000 (slight declines for non-Border and slight increases for Border areas).


3. From 1990 to 2000, the number of primary care physicians dropped in Texas from 64 to 57 per 100,000 people. This loss is primarily a result of a gain in population greater than the gain in the number of PCPs.

4. More PCSAs lost primary care physicians per population (55%) than gained them

(45%) from 1990 to 2000, despite a net increase in the overall number of PCPs, suggesting a growing maldistribution of PCPs across the State.

5. Urban PCSAs experienced a more-rapid decline in the number of primary care

physicians per population than rural PCSAs. The population-to-primary care physician ratio increased by 5.7% in urban PCSAs, twice the rate of 2% in rural PCSAs. However, while the decline was slower, the population-to-primary care physician ratio was already lower in the rural than the urban areas.

6. The rapid growth of the elderly population in the State resulted in a net loss of

approximately 20 primary care providers per 100,000 people age 65 and older on average across all PCSAs, raising questions about access to primary care among the elderly if current trends continue.

7. Approximately two-thirds of all PCSAs have no obstetrician-gynecologist. Although

the number of ob/gyn physicians increased by 137 between 1990 and 2000, the number of PCSAs without an ob/gyn decreased by only 1%, from 216 to 211.

8. On average, there was a net loss of almost 280 primary care providers per 100,000

Hispanics across all PCSAs in the State. This loss was more pronounced in non-Border regions of the State than in the Border regions, partially because the number of Hispanics as a percentage of the population increased at a faster rate in non-Border regions compared to Border regions.

9. The Border regions kept pace with the rest of the State in the number of PCPs per

population from 1990 to 2000. Rural/Border PCSAs had fewer PCPs per population that did rural non-Border PCSAs.

10. Rural PCSAs are more vulnerable to the loss of PCPs for three reasons:

a) Rural PCSAs have significantly smaller absolute numbers of PCPs (6.9 on

average) compared to urban PCSAs (72.2), increasing the impact of the loss of even one PCP.

b) Rural PCSAs are 3.58 times more likely to have 100% of their PCPs working 40 or more hours per week compared to urban PCSAs, increasing the risk of physician “burnout.”

c) In the average PCSA in Texas, almost one-third of the PCPs in active patient care in 1990 were no longer present in 2000. This lack of stability was more pronounced in rural areas.


Conclusions Examining trends in the distribution of the health workforce using more-natural boundaries, such as the distance from patients’ domiciles or places of work to physicians’ practice locations, can be advantageous. The Primary Care Service Areas (PCSAs) developed by the researchers of the Dartmouth Medical School are currently the only well-defined and carefully crafted alternatives to the county areas for organizing workforce data and conducting needs assessments and trend analyses from the prospective of actual clinical encounters or “natural market areas.” The approach produces a better clarification of the rural versus urban health workforce need differentials, but is limited by being anchored to only one point in time, while market areas, or “gravity fields,” of provider outreach change over time. Also, PCSAs depict only the spatial relationship of actual encounters between Medicare and some Medicaid patients and their providers. Finally, this perspective in defining the contours of physicians’ service areas is strictly provider-based, and does not include the health-care needs of populations that could or should possibly be served, but are not. Despite some limitations that strongly suggest the need for further research, the Primary Care Service Areas offer a realistic portrait of health-workforce shortages and geographic maldistribution of primary care physicians in Texas. Shortage and maldistribution are growing problems. The concern is especially acute for rural areas and for vulnerable segments of the population in Texas, specifically the elderly and Hispanic populations. Both rural and urban PCSAs suffered a loss of PCPs per total population from 1990 to 2000. When these problems are compounded with the high number of Texans without health insurance, and the relatively high rate of poverty in the State, the pressure on the primary care “safety net” Statewide may become overwhelming. For example, it is possible that the significant increase in the number of emergency rooms on “divert” status (diversion of patients to other hospitals when the emergency rooms reach a certain level of capacity) is a reflection of the growing crisis in access to primary care services in the State. For the elderly, the significant increase in the number of primary care physicians who no longer accept Medicare, when combined with the significant decrease in the number of primary care physicians per elderly from 1990 to 2000, may result in a significant barrier to adequate access to primary care services in the State. This is also true for Hispanics, the fastest-growing demographic segment of the population in Texas. The relatively high number of Hispanics in Texas without health insurance, combined with a significant decrease in the number of PCPs per Hispanic population, may pose an overwhelming obstacle to obtaining adequate primary care. Solutions to these problems may not be simple or direct and may require multiple multidisciplinary interventions. Unfortunately, current budget constrains may not allow the employment of the critical mass of resources needed to increase the number and improve the distribution of primary care physicians in the State. This is especially true when one considers that the length of time through the education and training “pipeline” – from entrance into medical school to active patient care practice – is seven years or more.


I. Background Health Professional Supply and Distribution Equitable delivery of primary care health services within the United States continues to be a challenge. A central factor in addressing this issue is ensuring an adequate supply and distribution of primary care providers relative to population needs for primary care services. Although primary care health-professional supply is most often examined with the outcome of access to care in mind, the supply and distribution of primary care providers relative to the population they serve has implications not just for access to care, but also for health-care utilization, costs, quality and outcomes (Grumbach K, Bodenheimer T. A primary care home for Americans: Putting the house in order. JAMA 2002; 288:889-893). Traditional primary care workforce analysis has considered numbers of providers at a fixed point in time, usually within administrative units such as States or counties in the U.S., or perhaps changes in numbers over a period of time within administrative units. These numbers are often related to total population within the same administrative units. Indeed, definitions of primary care Health Professional Shortage Areas are often dependent on such counts and are defined at the level of counties or county sub-areas. The difficulties in such approaches are: 1) primary care provider supply and distribution is changing, both over time and over space. For example, a recent study of primary care physician job turnover found that more than half (55%) of a group of PCPs younger than age 45 left at least one practice between 1987 and 1991 (Buchbinder S, Wilson M, Melick CF, Powe NR. Primary care physician job satisfaction and turnover. American Journal of Managed Care 2001; 7:701-703); 2) important defining characteristics of the primary care provider or of the population served are not taken into account when analyzing supply and distribution; 3) specific characteristics of the population, such as age, income or ethnicity, that determine need and demand for primary care services may not all be taken into consideration; and 4) defining primary care provider distribution by political administrative units such as counties or States may not at all reflect the service area or market area within which the services are provided. These factors limit understanding of primary care provider distribution across space and time, and the connection between primary care provider supply and distribution and health care quality and outcomes is tenuous. New methods or techniques of workforce analysis are needed.

Defining Natural Market Areas for Primary Care: Primary Care Service Areas (PCSAs) A significant barrier to evaluating primary care workforce supply and demand has been the lack of rational and well-defined geographic market areas for the delivery of primary care services. An innovative geographic information system project funded by


the U.S. Health Resources and Services Administration at Dartmouth Medical School resulted in defining natural market areas for primary care services (www.pcsa.hrsa.gov). The PCSA team used claims from the 1996 and 1997 Medicare files for this project. These Medicare files include the beneficiary (denominator) file, an enhanced Part B file, and the Outpatient file. The majority of Medicare primary care is found within the Part B file. A Standard Analytic File that includes the claims from a 5% sample of beneficiaries was used. Because only a few beneficiaries would be sampled in ZIP codes with low populations, this file was supplemented with a custom-run claims file that over-sampled ZIP codes with less than 2,800 beneficiaries. This ensured sufficient claims to make ZIP code assignments even in low-population ZIP codes. A 1999 area ZIP code file was used as one the primary building blocks of the PCSAs. Area, point and other ZIP codes were linked, and PCSAs were created by assigning each residential code to that code providing the plurality of primary care for Medicare beneficiaries, adjusting to ensure that all PCSAs are geographically contiguous. The goal of ensuring contiguity for each PCSA was to create units of analysis that are easily related to other geographic areas such as counties, census tracts, hospital service areas, hospital referral regions, and States. The assignment process is based on primary care utilization for more than 90% of all ZIP codes. The adjustment to ensure contiguity involves a reassignment protocol that balances utilization against contiguity and distance. Three further “requirements” are imposed upon PCSAs, and when these are not met, the PCSAs’ component ZIP codes are reassigned. First, PCSAs must have a total population of at least 1,000, the minimum population judged necessary to support a primary care clinician. Second, the Medicare beneficiaries must seek more of their primary care from within their residence PCSA than from any other. Third, at least 35% of the primary care of the beneficiaries must be delivered by providers within the same PCSA. It was decided to retain PCSAs with this relatively low level of primary care localization in order to identify areas that appeared to have trouble retaining their own population.

Thus, the PCSAs are empirically based definitions of service area boundaries that describe the actual pattern of local primary care use between patients and providers. Each PCSA is defined as a cluster of ZIP codes within which the bulk of residents receive primary care services from a physician whose practice lies within the same area. Primary Care Service Areas for Texas are shown in Figure 1. The advantage of such definitions is that they enhance the ability of health- workforce policy planners to better define both need for and access to primary care services by overcoming the last barrier mentioned above, that of analyzing primary care providers by arbitrary administrative units.


http://www.pcsa.hrsa.gov

Figure 1

Primary Care Service Areas with County Boundary Outline Overlay

South Texas Border Region

PCSA colors may cross county boundaries


Research Objectives

1. Determine the current geographic distribution of primary care physicians and non-physician clinicians by Primary Care Service Areas across Texas.

2. Examine the change in distribution of primary care physicians between 1990

and 2000 across Primary Care Service Areas in Texas. 3. Assess primary care physician availability to potentially vulnerable populations

across Primary Care Service Areas, and the trend of supply and distribution relative to these populations from 1990 to 2000.


II. Methods Construction of PCSAs for Texas The following methods were used for this project: 1) Boundary files and ZIP code definitions of PCSAs for Texas were obtained from the Dartmouth Project; 2) Primary care physicians and physician assistants were aggregated to the PCSA level using GIS programming routines and utilizing licensure data obtained from the Texas State Board of Medical Examiners for 1990, 1995 and 2000; and 3) Census block-group data from 1990 and 2000 for the State of Texas were aggregated to the PCSA level using GIS programming routines. Both total population and demographic characteristics of population, such as population by age or race/ethnicity, were calculated for each PCSA for 1990 and 2000. Licensure and census data were acquired from and prepared by the Health Information Network (HINET), a computer-based information management system developed by the Center for Health Economics and Policy (CHEP) of The University of Texas Health Science Center at San Antonio (UTHSCSA). HINET was created in 1991 and was designed to provide those who must make health-care decisions – legislators, program administrators, researchers, and health-care providers and users – with rapid access to reliable and continuously updated local information from many different sources.

Defining Primary Care Physicians Primary care physicians were defined, based on the work of Starfield and others, as family physicians, general practitioners, general pediatricians and general internists. A separate analysis was done for obstetrician/gynecologists (Starfield B. Primary care: concept, evaluation and policy. New York: Oxford University Press, 1992). Physicians were included in the analysis if they listed their activity as “active patient care” and if they listed a practice address in the State of Texas. Physicians with a missing practice ZIP code were assigned a ZIP code using their street and city practice address from the U.S. Postal Service ZIP code look-up database. Eight-digit ZIP codes were converted to five-digit ZIP codes for the purpose of matching each physician with a PCSA. A crosswalk file of ZIP code to PCSA obtained from the Dartmouth investigators was then used to assign each physician a PCSA. The number of physicians per 100,000 population was reported, although few of the PCSAs actually have 100,000 or more people, in order for results from this report to be comparable to others.

Definitions of Potentially Vulnerable Populations The analysis focused on three population groups and two geographic subdivisions within the State. The three population groups were chosen for their potential vulnerability to experience poor health outcomes when access to primary care is inadequate.


Children were the first vulnerable group. Children are high utilizers of primary care services. Potentially preventable hospitalizations and mortality have been shown to be related to poor access to primary care providers in this population (Gill J, Mainous A. The role of provider continuity in preventing hospitalizations. Arch Fam Med 1998; 7:352-357). Similar findings are true for those over age 65. Medicare patients in primary care health-professional shortage areas were significantly more likely to experience a preventable hospitalization compared to those living in areas without such a designation (Parchman ML, Culler SD. Preventable hospitalizations in primary care shortage areas: An analysis of vulnerable Medicare beneficiaries. Arch Fam Med 1999; 8:487-489). The third analysis focused on the Hispanic population of the State. This population has high rates of poverty and lack of health insurance compared to non-Hispanic whites, making Hispanics especially vulnerable to a lack of primary health-care services (Mayberry RM, Mili F, Ofili E. Racial and ethnic differences in access to medical care. Med Care Res Rev 2000; 8:44-48). They are also the fastest-growing demographic group within Texas. Analysis A GIS approach to analyzing the data offers several advantages:

1. It is possible to assign PCSAs to various geographic categories using GIS programming routines. The categories used below were Border versus non-Border and rural versus urban. These programming routines evaluated whether the centroid (the geographical center of a plane area) of each PCSA lay within or outside of current definitions of these geographic regions.

2. It is possible to examine the variation of primary care physicians across a more-

rational market area, the PCSA, by assigning physicians to each PCSA based on their practice ZIP code addresses.

3. It is possible to transfer data from the GIS program into a relational database in

order to conduct statistical analyses on the reconfigured data.

4. It is possible to examine visual maps of the data to look for patterns in the distribution in order to interpret the results of the statistical analysis, or suggest additional analyses that should be performed.

First, simple descriptive statistics were used to report on numbers and rates of primary care physicians for the State and across PCSAs. Maps of ratios and proportions were produced. Visual inspection of the maps often suggested trends in spatial distribution that were then analyzed in more detail. Means were compared with t-tests, either paired or independent, as indicated. Counts of categories were analyzed using a Chi-square statistic, with odds ratios calculated, if possible, along with 95% confidence intervals. P values for statistically significant comparisons are included, along with tabular results.


III. Results Demographics of Primary Care Service Areas: 1990 to 2000 To characterize the population by Primary Care Service Area, the percents of Hispanic

population, population under age 18, and population age 65 or older were reviewed, comparing Border versus non-Border PCSAs and rural versus urban PCSAs. Results are shown in Table 1. In each PCSA category, the percent of Hispanic population increased from 1990 to 2000. Urban PCSAs experienced a larger increase than rural PCSAs, and non-Border PCSAs had a larger increase than Border PCSAs. The percent of the population under age 18 in each PCSA decreased, with Border PCSAs experiencing the largest decrease. The percent of the population age 65 and older in each PCSA decreased on average across the State except in Border PCSAs, which experienced a small increase. This may represent the effect of a large in-migration of older retirees into this area of the State during the 1990s. The overall trends seem to reflect the advancing into middle age of the postwar baby boomers as well as the overall decline in birth rates. Thus, a slight overall decrease is detectable in the youngest and oldest age groups.

Table 1: Demographic Characteristics of Primary Care Service Areas

1990 2000 Change in % Total Population, Mean (S.D.)

47,175 (96,767)

57,900 (115,997)

22.7

(mean change=10,725) Percent Hispanic Total Border Non-Border Urban Rural

22.1 62.1 14.7 20.6 23.0

26.5 64.8 19.4 25.8 27.0

4.4 2.7 4.7 5.2 4.0

Percent Age less than 18 Total Border Non-Border Urban Rural

28.2 31.9 27.4 28.6 27.9

27.2 30.2 26.6 28.0 26.7

-1.0 -1.7 -0.8 -0.6 -1.2

Percent Age 65 or over Total Border Non-Border Urban Rural

14.8 11.9 15.3 10.6 17.6

14.1

-0.7 12.4 0.5 14.4 -0.9 10.5 -0.1 16.6 -1.0


Physician Supply In 1990, Texas State Board of Medical Examiners (TSBME) licensure data listed 28,526 physicians who classified their status as active patient care and had practice addresses in Texas. In 2000, the TSBME licensure data listed 31,287 physicians who classified their status as active patient care and had practice addresses in the State. The total number of active patient-care physicians increased by 9.7% from 1990 to 2000. The number of PCPs increased 10.6% over the same period. The older general practitioner population is in decline at the same time that there is an increase in the population of residency-trained family physicians. Although residency-trained family physicians are adequately replacing the general practitioner population, the net percent increase in physicians in these two categories was only 6.8% from 1990 to 2000, the lowest percent increase among the PCP categories and far behind the 22.7% increase in the State’s population. (Table 2.) The physician-to-population ratio in the State declined from 1990 to 2000. For all physicians, there was a 10.7% decline in the number of physicians per population. For primary care physicians, there was a 9.9% decrease from 1990 to 2000, despite a 10.6% increase in the overall number of primary care physicians. The supply of total physicians and primary care physicians did not keep up with the increase in the State’s population from 1990 to 2000.

Table 2: Number of Physicians in Texas: 1990 to 2000

1990 2000 Change 1990-2000 State Population 16,986,510 20,851,820 3,865,310 (22.7%) Number of Active Patient Care Physicians in Texas

28,526

31,287

2,761 (9.7%)

Active Patient Care Physicians per 100,000 population

168/100,000 150/100,000 -10.7%

Total Primary Care (% of total physicians)

10,620 (37.2%)

12,026 (38.4%)

1,406 (10.6%)

Primary Care per 100,000 population

64/100,000 58/100,000 -9.9%

Family Physician 3,359 4,341 982 (29.2%) General Practitioner 1,724 1,089 -635 (-36.8%) General Internist 3,543 4,249 706 (19.3%) General Pediatrician 1,994 2,347 353 (17.7%)


Primary Care Physician Supply and Distribution by PCSA: 1990 to 2000 Preliminary analysis of distribution of primary care physicians per population by PCSA revealed that in five of the PCSAs, the ratio of PCP per population in 1990 was more than three standard deviations above the mean. Two of these PCSAs, having much higher than average physician-to-population ratios, contained medical schools. The other three PCSAs consisted of a single ZIP code and were adjacent to PCSAs with PCP-per-population ratios less than the mean for the State. For this reason, these three PCSAs were felt to not truly reflect primary care market-area dynamics in 1990, six to seven years prior to the time period of the claims data that were used to construct the PCSAs. Therefore, in order to construct PCSAs that better reflect a primary care market area, these non-representative PCSAs were merged with contiguous PCSAs that met two criteria: their PCP/population ratio was less than the mean for the State, i.e. they were probably under-represented, and the street/highway access to the adjacent PCSA was superior to the other adjacent PCSAs. The same corrective analysis was done for PCSAs in 2000. This resulted in a decrease of 16 PCSAs for the State, dropping the total PCSAs from 360 to 344. The breakdown of total numbers by type of primary care provider as well as physician-to-population ratios and percentages is shown in Table 2. The mean number of primary care providers per 100,000 population within PCSAs declined by 2.9% between 1990 and 2000, as displayed in Table 3. This loss is equivalent to a decrease, on average, of two (almost three) primary care physicians for every 100,000 persons within each PCSA in the State. In actual practice, this average loss might represent a significant decline in the PCPs available within a small city or a rural Texas county.

Table 3: Primary Care Physicians per 100,000 by PCSA: 1990 and 2000 1990 2000 Change 1990-2000 Mean (S.D.) 51 (2.92) 49 (2.85) -2 (2.48) Range 0 – 285 0 – 384 -125 – 105 PCSAs with less than 1:3000

90 89 -1

PCSAs with no PCP

9 5 -4

When the ratio of PCPs per 100,000 population in 1990 is compared to that of 2000, 45% of PCSAs experienced a net gain of PCPs per population, while 55% of PCSAs experienced a net loss. The implication is that although the total number of PCPs increased by 1,406 from 1990 to 2000, there may be a growing maldistribution of PCPs Statewide. PCPs became more concentrated in fewer PCSAs during this time period. The distribution of PCPs per 100,000 population is shown in Figure 2. The shading represents PCSAs divided into quartiles of PCPs per 100,000 population, with the actual


interval values of the quartile categories displayed in the figure legend. The ratio of physicians to population in 2000 appears to be highest for PCSAs in the metropolitan counties. The heterogeneity of PCP-to-population ratios, even for PCSAs within the same counties, is also apparent. The change in PCP/100,000 from 1990 to 2000 is shown in Figure 3, and the actual interval values of the quartile categories are again displayed in the figure legend. This map suggests a growing maldistribution of providers in rural areas, here defined as the PCSAs within non-metropolitan counties, and also in urban areas, the PCSAs within metropolitan counties. The map visually demonstrates that much of the State is unable to maintain the former levels of local primary care physicians-to-population ratios, especially in rural areas. These observations are tested as hypotheses in subsequent sections of this report. PCSAs that overlap with adjacent States are represented in white if the majority of their areas are outside Texas.


Figure 2

Primary Care Physicians per 100,000 Population: 2000

Houston Dallas-Fort Worth

H


Figure 3

Change in Primary Care Physicians per Population: 1990 to 2000


A Comparison of PCSA PCP Supply to Shortage Area Designations One criterion for defining primary care Health Professional Shortage Areas (HPSAs) is a population-to-provider ratio of 3,000 to 1. Although other criteria, such as infant mortality and poverty, are factored into this definition, this type of ratio is key to assessing whether an adequate supply of primary care providers exists within an area to provide adequate primary care services. Typically, counties, or some rational combination of census tracts within counties, are used to establish a primary care HPSA. The rationale for combining census tracts within counties has not been based on known market or service areas for primary care services. First, the number and distribution of Primary Care Service Areas that met the 3,000-to-1 ratio were calculated for 1990 and 2000. Although the number of primary care physicians in the State increased by 1,406 over this time interval, the number of Primary Care Service Areas that met the criteria for a primary care HPSA decreased by only one, from 90 to 89 over this 10-year time period. Of the 90 PCSAs in 1990 with more than 3,000 people per PCP, 64.4% (n=58) still met this criteria in 2000. The distribution of PCSAs with more than 3,000 people per PCP in 2000 is shown in Figure 4 on the next page. The current primary care HPSA designations by county are shown in blue. The PCSAs with more than 3,000 people per PCP are shown as a red outline overlaying these counties. This map suggests that current primary care HPSA designations are not always consistent with the primary care providers-per-population ratios when calculated at the level of PCSAs. For example, many whole-county HPSAs in rural areas have no PCSAs with more than 3,000 people per PCP within their boundaries. Within large urban areas, such as Houston or Dallas-Fort Worth, there are partial-county shortage area designations, as shown in blue in Figures 5 and 6. PCSAs with more than 3,000 people per PCP are outlined in red. There appear to be few or no PCSAs with more than 3,000 people per PCP except in outlying areas surrounding the county.


Figure 4

Primary Care HPSAs: Overlay of PCSAs with more than 3,000 people per Primary Care Physician


Figure 5

Houston Partial-County HPSA: Overlay of PCSAs with more than 3,000 people per PCP

Figure 6

Dallas-Fort Worth Partial-County HPSA and PCSAs with more than 3,000 people per PCP


Primary Care Providers and Children Primary care for children and adolescents is provided by general pediatricians, family physicians and general practitioners. In this report, these specialties are defined as “pediatric providers.” There were 13 Primary Care Service Areas with no pediatric providers in 1990 and 12 in 2000. The number of pediatric providers per 100,000 people less than age 18 in each PCSA decreased 5.7% from 152 in 1990 to 143 in 2000, although the absolute number of pediatric providers increased from 7,075 in 1990 to 7,776 in 2000, a 10% increase (Table 4). These numbers may be deceiving, however, when one considers that the practice capacity for pediatric care in the offices of family physicians and general practitioners is not equivalent to that of general pediatricians. Family physicians and general practitioners provide care to all patients, regardless of age. If one were to assume that a single family physician or general practitioner were equivalent to a .33FTE pediatrician in terms of capacity within a practice to provide pediatric care, then the numbers would appear much different, as shown in Table 4, “pediatric FTEs” per 100,000 children. From 1990 to 2000, there was a 2.7% increase of six pediatric FTEs per 100,000 children less than age 5, and a 3.3% decrease of two pediatric FTEs per 100,000 children less than age 18 on average across all PCSAs.

Table 4: Pediatric Providers per 100,000 Less than Age 5 and Less than Age 18 by PCSA: 1990 and 2000

1990 2000 Change 1990-2000 Absolute number 7,075 7,776 701 Mean (S.D.) per 100,000 less than age 18

152.2 (93.4) 143.4 (129.6) -8.8 (108.3)

Mean (S.D.) per 100,000 less than age 5

574.9 (369.1) 568.3 (439.1) -6.6 (373.1)

Mean (S.D.) pediatric FTEs per 100,000 less than age 5

231.4 (202.4) 239.7 (239.1) 8.3 (143)


9.4 (75.4)a61.8 (51.9) 71.2 (110)

PCSAs with no peds provider 13 12 -1

a. 1990 versus 2000 p=0.019 Figure 7 shows the distribution of PCPs per 100,000 children under age 18 in 2000, and Figure 8 shows the change from 1990 to 2000.


Figure 7

Pediatric Primary Care Providers per 100,000 Less than Age 18

Figure 8

Change in Pediatric Providers per 100,000 Less than Age 18: 1990 to 2000


Primary Care Providers and the Elderly The number of primary care physicians who provide adult care, i.e. excluding pediatricians, per 100,000 population age 65 and over was examined in each PCSA. As shown in Table 5, the availability of primary care providers to the elderly by PCSA decreased by 4.8% between 1990 and 2000, from 370 to 353, for a net change of 17 primary care providers per 100,000 elderly in each PCSA over this 10-year time period. This drop is largely a result of the increase in the elderly population relative to the increase in the number of primary care providers, since the number of family physicians, general practitioners and general internists increased by 1,053 over this same time period. There was a 20.8% increase in the population age 65 and over from 1990 to 2000, but only a 12.2% increase in family physicians, general practitioners and general internists over the same time interval. Figure 9 shows the distribution of PCPs per 100,000 elderly in 2000. The areas with the highest concentration of PCPs per elderly are urban areas. Rural areas had the lowest concentration of PCPs per elderly. (See Rural/Urban Distribution of Primary Care Providers in subsequent section of this report.) As shown on the map in Figure 10, a decrease in primary care providers per 10,000 elderly was common across rural areas. Ten of the PCSAs had no PCPs for the geriatric population in both 1990 and 2000. Only two of the PCSAs with no PCPs per elderly in 1990 also had no PCPs per elderly in 2000. Eight PCSAs gained a PCP and eight lost PCPs relative to the elderly.

Table 5: Primary Care Providers per 100,000 Age 65 and Over by PCSA: 1990 and 2000

1990 2000 Change 1990-2000

-17.1 (179.7)aMean (S.D.) 370.2 (297.8) 353.1 (301.8) Total State population 65 and older

1,715,526 2,071,534 20.8%

Number of FP/GP/IM

8,624 9,679 12.2%

PCSAs with no geriatric provider

10 10 0

a. 1990 versus 2000 p=0.072


Figure 9

Primary Care Physicians per 100,000 Age 65 or over: 2000

Figure 10

Change in Primary Care Physicians per 100,000 Age 65 or over: 1990 to 2000


Obstetricians by Primary Care Service Area Physicians who listed their primary specialty as obstetrics/gynecology (ob/gyn) were included in this analysis. The number of ob/gyns in active patient care in Texas in 1990 was 1,750, and increased to 1,887 in 2000. This resulted in a modest gain of 0.9 in the number of ob/gyns per 100,000 women by PCSA over the same time interval. However, the geographic distribution of ob/gyn providers across PCSAs reveals that 60% of PCSAs had no ob/gyn physician in 1990, and 59% had none in 2000 (Table 6). As shown in Figure 11, ob/gyn providers are predominantly located in PCSAs within larger population centers in Texas, outside of rural areas. Women outside these population centers are largely dependent upon the services of family physicians and general practitioners for their care. In 2000, the number of women in PCSAs with an ob/gyn totaled 9,338,598. The number of women in PCSAs without an ob/gyn totaled 1,156,428. Thus, 11% of the women in Texas live in a Primary Care Service Area without an ob/gyn physician.

Table 6: Ob/gyn Providers per 100,000 Females by PCSA: 1990 and 2000

1990 2000 Change 1990-2000 Mean (S.D.) 7.2 (12.8) 8.2 (25.7) 1.0 (19.3) Range 0 – 116 0 – 457 -64 – 341 PCSAs with no ob/gyn provider

216 (60%) 211 (59%) -5 (-1%)

Figure 11

Number of Obstetricians in each Primary Care Service Area: 2000


Primary Care Providers and Hispanics The fastest-growing segment of the population in Texas is the Hispanic population. From 1990 to 2000, this population increased by 32% and was responsible for 60% of the growth in the State’s population. Hispanics are unique in their health-care needs because of differences in language, culture, and a relative lack of health insurance compared to other populations. Hispanics represent one-third of the State’s population and 50% of the State’s uninsured population (Characteristics of Texans with and without health insurance. Texas Department of Insurance, State Planning Grant Division, January 2002). The ratio of primary care providers to Hispanic population by PCSA in 1990 and 2000 was analyzed. The results are shown in Table 7 and Figures 12-13. From 1990 to 2000, there was a decrease, on average, of almost 280 primary care providers per 100,000 Hispanics by Primary Care Service Area within Texas. This decrease is not surprising, given the fact that the Hispanic population growth outpaced the increase in number of PCPs in the State by a 3-to-1 ratio from 1990 to 2000 (32% to 10.6%). The relatively high number of PCPs per 100,000 Hispanics is best understood when one considers that many PCSAs with high numbers of PCPs have relatively low numbers of Hispanics, especially in the north and eastern areas of the State (see Figure 12). As Figure 13 demonstrates, the largest decrease in PCPs per Hispanic population occurred in PCSAs away from the Texas-Mexico Border. This is a product of a stagnant growth of PCPs in these areas, coupled with a rather significant increase in population, largely Hispanic. There was a 76.2% increase in the Hispanic population in non-Border PCSAs, compared to a 31.4% increase in Border PCSAs. Conversely, the mean number of PCPs per 100,000 non-Hispanic whites by PCSA increased from 84 to 91 from 1990 to 2000. An advantage of conducting this analysis using PCSAs is that certain comparisons at the PCSA level provide greater insights than those conducted at the State level. One example is the number of PCPs per 100,000 Hispanics. In 1990, there were 251 PCPs per 100,000 Hispanics in the State. In 2000, the number dropped to 181 per 100,000 Hispanics – a 38.7% decrease. Although the percent decrease is comparable to that analyzed at the PCSA level, the PCSA analysis reveals far fewer PCPs per 100,000 Hispanics than the State-level calculation. This difference is a reflection of apportioning the Hispanic population and the PCPs to actual primary care market areas for the PCSA analysis.

Table 7: Primary Care Providers per 100,000 Hispanics by PCSA: 1990 and 2000 1990 2000 Change 1990-2000

-279.4 (592.4)aMean (S.D.) 699.1 (1,013.7) 419.7 (630.7) Range 0 – 9,091 0 – 7,142 -3,715 – 1,431 PCSAs with no PCP provider 9 5 4

a. 1990 versus 2000 p<0.001


Figure 12

Primary Care Physicians per 100,000 Hispanics: 2000

Figure 13

Change in Primary Care Physicians per 100,000 Hispanics: 1990 to 2000


The Border Region The Texas-Mexico Border Region experienced a rapid increase in population over the 1990s. This region is characterized by high rates of poverty; a high percentage of children under age 5 (10%, compared to a national proportion of 6.8% in 2000 census data); a high number of uninsured residents; and a high concentration of Hispanics. PCSAs were assigned as being Border or non-Border, using the 43-county area the Texas State Comptroller’s Office designates as the Texas Border Region. Based on this assignment, Border PCSAs were compared with non-Border PCSAs (see Table 9). One method of evaluating the need for services in a population is to calculate a “dependency ratio.” This ratio reflects the relative proportion of those over age 65 and under age 18 to those between the ages of 18 and 65. Those over 65 and under 18 are more likely to depend on those between the ages of 18 and 65 for support. A higher ratio may reflect a more “vulnerable” population, one that has fewer working-age adults to support its needs for both social and health care services. The dependency ratios for the Border Region compared to the remainder of the State are displayed in Table 8. The 32-county Border Region consists of those counties within 100 miles of the Texas-Mexico Border, and the 43-county Border Region is made up of those counties within 300 miles of the Border Region. Either definition reveals that the Border Region has a higher dependency ratio compared to the non-Border areas of the State, due to both a higher youth dependency and a higher aged dependency. There were fewer PCPs per 100,000 total population in Border PCSAs compared to non-Border PCSAs in both 1990 and 2000. Overall, the difference in PCP/100,000 between Border and non-Border PCSAs decreased from 1990 to 2000. The major loss of PCPs per 100,000 Hispanics occurred in non-Border PCSAs compared to Border PCSAs. Although there was a net loss of 10 PCPs per 100,000 Hispanics in Border PCSAs, non-Border PCSAs experienced a loss of 329 PCPs per 100,000 Hispanics. Half of all Border PCSAs experienced a gain in the number of PCPs/100,000, compared to only 44.1% of non-Border PCSAs. Although this is an interesting preliminary finding, further exploration of the data is needed because it does not correspond with other evidence concerning problems with access to primary health care for the population in the Border Region. A possible explanation lies in the observation that the number of PCPs per population in Border PCSAs more closely resembles that found in rural non-Border PCSAs, as shown in the next section of this report. It is possible that the relatively large number of rural PCSAs in the non-Border Region of the State may mask differences in PCP supply and distribution between Border and non-Border PCSAs. When Border and non-Border PCSAs are divided into rural and urban PCSAs, it is revealed that rural/Border PCSAs had fewer PCPs per population than did rural/non-Border PCSAs in both 1990 and 2000 (Table 9). Comparing urban/Border PCSAs and urban/non-Border PCSAs, there was no difference in PCPs per population.


Table 8: Dependency Ratios and Demographics: 1990 to 2000

Texas 32 County

Non-32 County

43 County

Non-43 County

1990 Dependency Ratio 0.63 0.84 0.61 0.72 0.61

Youth Ratio 0.46 0.65 0.45 0.55 0.44 Aged Ratio 0.16 0.19 0.16 0.17 0.16

2000

Dependency Ratio 0.62 0.80 0.61 0.71 0.60 Youth Ratio 0.46 0.61 0.45 0.53 0.44 Aged Ratio 0.16 0.19 0.16 0.18 0.16

Demographics 1990 and 2000

(ratio 2000/1990)

Overall Population 1.23 1.24 1.22 1.21 1.23 Hispanic 1.54 1.34 1.62 1.31 1.76

65 and Older 1.21 1.34 1.19 1.28 1.19 Less than 18 1.22 1.21 1.22 1.18 1.23

Table 9: Border and Non-Border PCSAs

(Means and Standard Deviations) 1990 2000 Difference

PCP/100,000 Border Non-Border

44.4 (21.5) 52.3 (30.5)a

45.5 (23.2) 50.2 (29.4)

1.1 (18.0) 4.5% -2.1 (25.8) -4%

Pediatric FTE/100,000 age less than 18 Border Non-Border

48.1 (29.7) 64.3 (54.6)b

56.7 (36.5) 73.8 (118.6)

8.6 (28.1) 18.1%c

9.5 (81.2) 14.8%d

PCP/100,000 elderly Border Non-Border

336.2 (142.2) 376.5 (318.1)

327.6 (176.7) 357.8 (319.6)

-8.6 (1478.6) -2.4% -18.7 (185.2) -4.8%e

PCP/100,000 Hispanic Border Non-Border

101.4 (114.6)

809.2 (1065.2)f

91 (86.1)

480.3 (668.1)g

-10.4 (50.6) -10.9%

-328.9 (632) -40.7%h

Rural/Urban Comparisons: 40 (21) Rural Border -1 (19) -2% 41 (20)

50 (26)i 49 (.23)j Rural Non-Border -1 (27) -2% a.Border versus Non-Border 1990 p=0.064 b.Border versus Non-Border 1990 p=0.031 c.1990 versus 2000 Border p=0.025 d.1990 versus 2000 Non-Border p=0.042 e.1990 versus 2000 Non-Border p=0.080 f.Border versus Non-Border 1990 p<0.001 g.Border versus Non-Border 2000 p<0.001 h.1990 versus 2000 Non-Border p<0.001 i.Border versus Non-Border 1990 p=0.037 j.Border versus Non-Border 1990 p=0.028


Rural/Urban Distribution of Primary Care Providers PCSAs were designated as rural or urban through use of a GIS program, which assigned PCSAs based on whether their geographic centroid fell within a county not within a metropolitan statistical area as defined by the 2000 census. This resulted in 214 PCSAs (59.4%) receiving a rural designation, and the remainder an urban designation. From 1990 to 2000, there was a 10.2% increase in the absolute number of PCPs in rural PCSAs, from 1,346 to 1,483. There was a 10.7% increase of PCPs in urban PCSAs, from 9,525 to 10,548. For 2000, the numbers and changes of PCPs per 100,000 total population, children, elderly and Hispanics are shown in Table 10. There was a significant difference in the number of PCPs per 100,000 elderly between rural and urban PCSAs in 1990 and 2000, and in the number of PCPs per 100,000 children in both years. Urban PCSAs had the largest mean decrease in PCPs per 100,000 elderly in 1990 and 2000, -40.8/100,000, compared to rural areas with only a –0.9/100,000 decrease (t-test=2.078, p=.014). Urban areas experienced a significant increase in the number of pediatric providers compared to rural regions from 1990 to 2000 (t-test=-2.97, p=.022). None of the other differences were significant. These findings are illustrated in Figure 8 for children and Figure 10 for the elderly.

Table 10: Rural/Urban PCP/100,000 Comparisons

1990 2000 Difference PCP/100,000 Rural Urban

48.7 (25)

54.4 (34.6)a

48.1 (23.2) 51.5 (35)

-0.6 (26.1) -2% -2.9 (22.7) -4%

Pediatric FTEs/100,000 less than age 18 Rural Urban

57.4 (34.9) 68.1 (69.3)b

59.7 (41) 88.9 (164.3)c

2.3 (38.6) 4% 20.8 (108.1) 30.5%d

PCP/100,000 elderly Rural Urban

276.4 (151.8) 507.7 (392.1)e

275.5 (148.9) 466.9 (413.7)f

-0.9 (164.8) -0.3% -40.8 (197.8) -8%g

PCP/100,000 Hispanics -275.8 (624.9) -38%h Rural 713.9 (103.2) 438.1 (673.9) -284.6 (543.3) -42%i Urban 677.4 (987.6) 392.8 (562.7)

a. Rural versus Urban 1990 p=0.077 b. Rural versus Urban 1990 p=0.054 c. Rural versus Urban 2000 p=0.011 d. 1990 versus 2000 Urban p=0.022 e. Rural versus Urban 1990 p<0.001 f. Rural versus Urban 2000 p<0.001 g. 1990 versus 2000 Urban p=0.014 h. 1990 versus 2000 Rural p<0.001 i. 1990 versus 2000 Urban p<0.001

Much has been made of the shortage of primary care physicians in rural areas. The Texas Statewide Health Coordinating Council’s report on trends in health professionals for the State reported, in a county-level analysis of primary care physicians for 1999, that 27 counties had no primary care physician and 20 had only one primary care physician, all


within rural areas. The Council went on to report that the population-to-PCP ratio in rural areas, aggregated to the county level, was 2,125:1, approximately 43% higher than the urban ratio of 1,491:1. As mentioned earlier, one advantage of using Primary Care Service Areas, rather than counties, as the unit of analysis is that these areas reflect actual market areas or utilization areas for patients in rural areas that often combine counties. Often, the PCSA will include only a portion of a county or portions of two adjacent counties. A PCSA also may include an entire county combined with a portion of an adjacent county. Analysis of the population-to-PCP (including ob/gyn physicians) ratio at the PCSA level yielded very different results than the analysis done at the county level. In 2000, the population-to-PCP ratio in rural PCSAs was 2,477:1, only 2.3% higher than the urban PCSA ratio of 2,421:1. Compared to 1990 data, both urban and rural PCSA population-to-PCP ratios increased. In rural PCSAs, the ratio increased from 2,425:1 to 2,477:1, a 2% increase, while in urban PCSAs, the ratio rose from 2,122:1 to 2,421:1, a 5.7% increase. This analysis points out the advantage of using PCSAs for workforce analysis, as the county-level analysis obscures the variation and change in PCP distribution across true market areas for primary care.


Primary Care Provider Work Effort Physician licensure data provides an estimate of the amount of time spent in direct patient care, divided into four categories: 40 or more hours per week, 20 to 39 hours per week, 1 to 19 hours per week, and 0 hours per week. The distribution of primary care physicians by time spent in direct patient care is shown in Table 11 for 1990 and 2000. There was an increase of 8.1% in the number of primary care providers who spent 40 or more hours each week in direct patient care from 1990 to 2000. Direct patient-care hours of PCPs in rural PCSAs were compared to PCPs in non-rural PCSAs. The results are shown in Table 12. There was little change in the percent of PCPs who worked 40 or more hours per week from 1990 to 2000; however, there was a 5.8% increase in the number of PCPs who worked 40 or more hours per week in urban areas. It is possible that this larger increase in work effort among PCPs in urban areas is a product of the more-rapid increase in population-to-PCP ratio observed in urban compared to rural areas. A calculation of the percent of PCSAs that had an increased number of PCPs working 40 or more hours per week revealed no difference between rural and urban areas. The map in Figure 14 shows the percent of PCPs in each PCSA who worked 40 or more hours each week. Rural PCSAs more commonly were the areas where 90% to 100% of PCPs worked this many hours. This hypothesis was tested by dividing the PCSAs into those where 100% of PCPs worked 40 or more hours each week and those where less than 100% of PCPs worked this amount. The analysis showed that rural PCSAs were 3.58 times more likely to have 100% of the PCPs working 40 or more hours per week compared to urban PCSAs (95% C.I. 2.38, 6.66). The latter finding is an example of how GIS analysis can serve as an exploratory tool to develop hypotheses that can then be tested by more-formal statistical methods. Without the mapping as shown in Figure 14, this would not have occurred.

Table 11: Percent Time Spent in Direct Patient Care

1990 2000 Change More than 40 hours per week 80.2 88.3 8.1

20-39 hours 10.7 8.8 -1.9 1-19 hours 7.1 2.7 -4.4 0 hours 1.9 0.1 -1.8

Table 12: Percent in Direct Patient Care more than 40 hours per week Average Percents

1990 2000 Change 1990-2000 Rural 86.6 (16.8) 86.9 (19.1) 0.3 (5.2) Urban 83.1 (13.2)a 88.3 (11.2) 5.2 (15.6)b

Rural-Urban Difference 3.5% -1.4% a. Rural versus Urban 1990 p=0.030

b. 1990 versus 2000 Urban p<0.001


Figure 14

Percent in Direct Patient Care 40 or more hours per week


Stability of the Primary Care Provider Workforce in Texas (turnover ratios by PCSA 1990 to 2000 compared to State average) Primary care physician turnover in Texas from 1990 to 2000 is indicated by three statistics: (1) 22.7 % of the PCPs in 1990 were no longer in active patient care in 2000; (2) 29.5% of the PCPs in 2000 had not been in active patient care in 1990; and (3) 47.9% were in active patient care in both 1990 and 2000. The percent of PCPs who were in active patient care in both 1990 and 2000 in the same PCSA was calculated. Eleven PCSAs had a complete turnover in PCPs from 1990 to 2000, and 62 experienced no turnover in PCPs, either loss or gain. The mean percent of PCPs who were in practice in the same PCSA in 1990 and 2000 was 70.2, with a standard deviation of 22.1. On average, 29.6% of primary care physicians who were in active practice in 1990 were no longer in practice in the same PCSA by 2000. They retired, died, left the State or were practicing in a different PCSA. Figure 15 presents the distribution of the percent of PCPs who were in practice in 1990 by PCSA, but who were not present in the same PCSA in 2000. There were no significant differences in this rate of instability between Border (26.1%) and non-Border (30.3%) PCSAs, or between rural (29.9%) and urban (29.3%) PCSAs.

Figure 15

Instability of PCPs: 1990 to 2000


Physician Assistants The distribution of physician assistants within Texas was analyzed. The Texas State Board of Medical Examiners began licensing physician assistants in 1996. Licensure data for PAs in 2000 were analyzed for supply and distribution. Physician assistant data for 1990 are available from a directory of the membership of the State PA association, but may not be comparable to licensure data. A second problem encountered is that the licensure data for PAs do not include specialty information. Thus, the data shown here for PAs are reflective of all PAs, not just those practicing in primary care. It may be possible to obtain data on membership in the State PA association for the year 2000, compare that to licensure data for 2000, and assess the validity of comparing membership data from 1990 to that of 2000. An advantage of the membership data is that they contain specialty information, unlike licensure data. This preliminary analysis of PA licensure data from 2000 revealed that all but 34.3% of PCSAs had at least one PA with a practice address in that PCSA. The mean number of PAs per 100,000 population in 2000 in each PCSA was 7.9 (S.D. 9.7). There were significantly more PAs per 100,000 population in rural PCSAs, 9.2, than in urban PCSAs, 6.9 (t-test=2.13, p=.04). A rural PCSA was 1.37 times more likely to have a PA than an urban PCSA (95% C.I. 1.17, 1.61). Figure 16 shows the number of PAs in each PCSA across the State.

Figure 16

Number of Physician Assistants within each PCSA: 2000


Comparison of PCSA Analysis to County-Level Analysis Most reports of physician supply and distribution in Texas have been conducted at the county level. In order to compare the results of this PCSA-based report to traditional reports, a county-level analysis of physician supply and distribution in the State was performed from the primary data sources: the 1990 and 2000 Texas State Board of Medical Examiners licensure data. Just as in the PCSA analysis, active patient-care physicians who listed practice addresses in the State of Texas were included. Physicians were aggregated to the county level using a county identifier field in the licensure data or assigning the practice addresses to a county, if the county-level variable was missing. Results of the analysis are shown in Table 13.

Table 13: Comparison of Physicians to 100,000 Population at PCSA-Level and County-Level Analysis

(relaxed alpha criteria of p=<0.10) 1990 County 2000 County 1990 PCSA 2000 PCSA PCP/100,000 42.9 (25) 41.4 (23.9) 51 (29.4) 49 (28.6) Pediatric FTEs/100,000 less than 18

50.5 (33.9) 48.8 (32.2) 61.8 (51.8) 71.2 (111)a

PCP/100,000 age 65 or over

288.6 (196) 273.7 (181.2) 370 (297.8) 353 (301.9)

PCP/100,000 Border Non-border

37.9 (23.6) 43.9 (25.2)

37 (21.1)

42.3 (24.5)

44 (21.5)

52.2 (30.5)b

45 (23.2)

50.2 (29.4) PCP/100,000 Rural Urban

40.6 (25) 39.3 (23.9) 48.8 (25) 48.1 (23.2)

50.6 (23.6)c 48.4 (23)d 54.4 (34.6)e 51.5 (35) a. p=0.019 PCSA 1990 versus 2000 b. p=0.064 PCSA 1990 Border versus Non-Border c. p=0.007 County 1990 Urban versus Rural d. p=0.011 County 2000 Urban versus Rural e. p=0.077 PCSA 1990 Urban versus Rural In every instance, the trend in physician supply is the same. The “central tendency” of physician per population for PCSAs tends to be higher than that of counties because relatively few PCSAs have no physicians compared to counties. The one exception is that of urban counties, which are divided into multiple PCSAs, thus decreasing the mean number of providers per population within urban PCSAs compared to physicians per population at the county level. To allow for comparison of results, the tables for county-level data such as those already presented for PCSAs are supplied in Appendix 1.


IV. Discussion Although there was an increase in the absolute number of PCPs in the State from 1990 to 2000, the rapid growth of the State’s population resulted in a net loss of PCPs per population. This Primary Care Service Area analysis provides additional insights into the nature of this phenomenon.

a) There was a net loss of primary care physicians per population in the State from 1990 to 2000, from 64 to 58 per 100,000 people. This loss is primarily a result of a gain in population greater than the gain in number of PCPs.

b) This loss was more pronounced in urban areas, where the population-to-PCP

ratio decreased by 4%, twice the 2% decrease observed in rural areas.

c) There was a growing maldistribution of primary care physicians across natural market areas for primary care from 1990 to 2000. This conclusion is supported by the finding that more PCSAs lost primary care physicians (55%) than gained primary care physicians (45%) from 1990 to 2000, despite a net increase in the overall number of PCPs.

d) The elderly may experience a growing problem with accessing a primary care

provider as a result of the net loss of 17 primary care providers on average per 100,000 people age 65 and older across all PCSAs. Recent reports of primary care physicians closing their practices to new Medicare patients may only compound this problem.

e) When analyzed at the level of natural market areas for primary care services,

there was almost no improvement in the distribution of obstetrician/ gynecologists in the State, although the number of ob/gyn physicians increased by 137 between 1990 and 2000. During the decade, the number of PCSAs without an ob/gyn physician decreased by only 1%, from 60% to 59%.

f) The Hispanic population of the State may have problems accessing a primary

care provider. There was a net loss of almost 280 primary care providers per 100,000 Hispanics on average across all PCSAs in the State. This loss was more pronounced in the non-Border region. This region experienced a significant increase in Hispanic population during this time period without a corresponding increase in primary care providers.

g) Although the Border Region of the State experienced an increase in the

number of PCPs per population from 1990 to 2000, the Border had fewer PCPs per population both in 1990 and 2000. The observed increase, when calculated at the PCSA level, was negligible.


h) Rural PCSAs are more vulnerable to loss of PCPs than urban PCSAs for three reasons:

• Physician “Burnout”: Rural PCSAs are 3.58 (95% confidence

interval 2.38, 6.66) times more likely to have 100% of their PCPs working 40 or more hours per week compared to urban PCSAs, increasing the risk of physician “burnout”;

• Smaller Numbers: Rural PCSAs have significantly smaller absolute

numbers of PCPs on average (6.9) compared to urban PCSAs (72.2). Thus, the loss of even one PCP in a rural PCSA would have a much greater impact than in an urban PCSA.

• In the average PCSA in Texas, almost one-third of the PCPs who

were in active patient care in 1990 were no longer present in 2000. This lack of stability was more pronounced in rural areas.

Similarities and Contrasts to Previous Reports of PCPs in Texas The Texas Statewide Health Coordinating Council, with the assistance of the Health Professions Resource Center in the Texas Department of State Health Services, released a report of trends in health professional supply in 1999 (http://www.tdh.state.tx.us/stateplan01). Based on analysis of physician licensure data from 1999, the Council found approximately 30,400 active physicians in the State. This is comparable to the above report’s count of 31,287 active physicians, obtained from licensure data for 2000. The Council’s definition of primary care physicians included specialists in obstetrics and gynecology, making it difficult to compare with data in the above report. However, the Council counted approximately 12,800 primary care physicians in active patient care in 1999. This number compares favorably to the above report’s count of 12,026 in 2000, especially if one includes obstetricians who were counted in the above report’s total of primary care physicians. Regarding the geographic distribution of primary care physicians, the Council found that 26 of the 254 counties in the State had no primary care physician, and 20 had only one PCP. These counties were all located in rural areas of the State. This finding is consistent with the above analysis by PCSA. However, because PCSAs in rural areas often encompass more than one county in order to include areas with a primary care physician, the above analysis found only 5 PCSAs without a primary care physician in 2000. The Council report cites a ratio of primary care physicians to population of 57 to 66 per 100,000 in 1999, similar to the ratio reported above of 64 in 1990 and 58 in 2000. The Council also reported a gap in primary care physician supply between rural and urban areas: Urban areas had 67 PCPs/100,000 and rural areas had 47/100,000 in 1990, when calculated at the county level rather than by PCSA.


http://www.tdh.state.tx.us/stateplan01

Finally, this PCSA analysis is compared to current primary care Health Professional Shortage Area designations on pages 17-20. The differences noted should be interpreted with some caution because of the multiple criteria that often are used to designate a county or sub-county area as a shortage area. However, the starting point for HPSA designation remains either a 3,500-to-1 population-to-primary care physician ratio, or 3,000 to 1 if other criteria such as birth rates and poverty are taken into consideration. Using this lower cutoff of 3,000 to 1, significant discrepancies were found between current HPSA designations and PCSAs with 3,000:1 or higher ratios.

Difficulties Encountered in PCSA Analysis From a methodological perspective, perhaps one of the most important insights provided by this analysis is that PCSAs may not truly represent “service” areas. That is, several PCSAs with many physicians and very few people were more than two standard deviations above the mean physician-to-population ratio. At the extreme, several PCSAs had a population-to-primary care physician ratio of approximately 300 to 1, compared to an overall mean of approximately 2,000 per population. Although it is true that the majority of the population within those PCSAs also obtained the majority of their care within that PCSA, it is unlikely that this population could support this high number of physicians. These physicians most likely drew patients from several other surrounding PCSAs, but not enough of the total population from that PCSA to result in combining these PCSAs into one PCSA. So, by starting with patient claims data, one can say that PCSAs represent a patient market area, but not a physician service area. Another difficulty encountered was the need to run complicated GIS programming routines to match census block-group data from both 1990 and 2000 to PCSAs, to use current definitions of rural versus urban areas and Border versus non-Border areas, and to do the difficult matching of physician practice ZIP code to PCSA. It is entirely possible that these Primary Care Service Areas will change over time, and perhaps significantly, especially if the observed trend of decreasing PCP supply and growing maldistribution in the State continues. Further study of this phenomenon is needed.

Opportunities Discovered in PCSA Analysis: Turnover/Stability Ratios Several unique opportunities for workforce analysis were uncovered by taking a GIS approach using PCSAs. First, it was possible to compare rural versus urban areas and Border versus non-Border areas based on true market areas for the delivery of primary care rather than at the county level. By mapping physician distribution by PCSA, two hypotheses were developed that were formally tested by exporting the data from the GIS database into a statistical database: 1) When physician work effort was mapped, a potential difference between urban and rural PCSAs was discovered and subsequently


tested, and 2) mapping of PCPs per children under age 18 and PCPs per population age 65 and older suggested rural urban maldistributions that were subsequently tested statistically.

Advantages of PCSA Analysis Two questions are worth asking. First, is there an advantage to using PCSAs as a unit of analysis rather than counties, especially since, as shown in Table 15, the trends are similar? That is, are there any new insights or findings when analysis is done at the PCSA level that are obscured when the same analysis is done at the county level? If so, is the nature of these findings so compelling as to warrant further use of PCSAs and perhaps even further development in refining their definition and advancing the use of GIS as a workforce-analysis tool? Three examples provide evidence to support the use of PCSAs over the traditional county-level analysis.

1. At the county level in 1999, 26 of the State’s 254 counties had no PCP. However, when examined at the level of a natural market area for primary care, only three PCSAs had no PCP in 2000. The explanation for this discrepancy is twofold. First, by definition, a PCSA must have contained at least one PCP in 1998 or 1999 to be classified as a PCSA by the clustering methodology used to create PCSAs. Second, many of the rural counties, especially in the western half of the State, with no PCP are merged into one or more adjacent counties with PCPs.

2. At the sub-county level within metropolitan areas, an examination of the supply

and distribution of PCPs by PCSAs provides insight into the primary care physician workforce that is obscured by a county-level analysis. For example, an examination of PCSAs with a ratio greater than 3,000:1 or more population to PCP reveals that for the metropolitan Dallas-Fort Worth and Houston areas, these “short” PCSAs are mostly located in the fringes of these metropolitan regions, not in the urban cores. There is no doubt that other criteria are met within urban core areas to qualify them as primary care HPSAs (poverty, etc.), but the minimum criterion of a ratio greater than 3,000:1 is not met within these natural market areas for primary care.

3. At the county level, many counties that are classified as HPSAs have no PCSAs

with greater than 3,000:1 population-to-PCP ratios that overlap their boundaries. Again, counties are not rational market areas for primary care. It is possible, for example, that a county with no PCP may have on its Border, in an adjacent county, a large population center with an adequate number of PCPs to serve the area.


V. Future Research The findings of this project suggest several unique research opportunities. First, it will be possible to build on the experience gained by developing predictive models relating the change in PCP supply and distribution by PCSAs to the characteristics of the population in each PCSA. Second, it is suggested that similar analyses would be useful for other States in the South Central Region. Third, in order to further develop GIS techniques in informing policy on the health professional workforce, one must take the next step in GIS analysis and begin geocoding the practice addresses of physicians so that their actual distribution relative to underlying population density and characteristics can be studied. (Geocoding uses a street address and ZIP code database to plot points on a map showing the location of a physician’s practice.) Finally, working with Primary Care Service Areas provided suggestions on how to re-evaluate their definition in future enhancements of this important analytical tool.


Appendix 1

County-Level Tables

Table 1: Primary Care Physicians per Population by County: 1990 and 2000 1990 2000 Change 1990-2000 Mean (S.D.) 42.9 (25.4) 41.4 (23.9) -1.5 Range 0 – 139.1 0 – 119.4 -139.1 – 94.2 Counties with less than 1:3,000

171 166 5

Counties with no PCP

24 27 -3

Table 2: Pediatric Providers per 100,000 Less than Age 18 by County: 1990 and 2000

1990 2000 Change 1990-2000 Absolute number 7,075 or 7,072 7,776 or 7,699 701 or 627 Mean (S.D.) per 100,000 less than age 18

128.9 (82.2) 118.6 (75.6) -10.3 (72.6)

Mean (S.D.) per 100,000 less than age 5

484 (317.6) 479.3 (316.9) -4.7 (295.7)


188 (125.7) 195.2 (129.1) 7.2 (117.6)


50.5 (33.9) 48.8 (32.2) -1.7 (29.6)

Counties with no peds provider 26 31 5


Table 3: Primary Care Providers per 100,000 Age 65 and Over

by County: 1990 and 2000

1990 2000 Change 1990-2000 Mean (S.D.) 288.6 (196) 273.7 (181.2) -14.9 (157.2) Total State population 65 and older

1,715,526 2,071,534 20.8%

Number of FP/GP/IM

8,618 9,588 11.3%

Counties with no geriatric provider

25 27 -2

Table 4: Ob/Gyn Providers per 100,000 Females by County: 1990 and 2000 1990 2000 Change 1990-2000 Mean (S.D.) 5.3 (8.9) 5.6 (9) 0.3 (4.6) Range 0 – 59 0 – 46 -25.7 – 17.8 Counties with no Ob/Gyn provider

165 (65%) 163 (64.2%) -2

Table 5: Primary Care Providers per 100,000 Hispanics by County: 1990 and 2000

1990 2000 Change 1990-2000

-226.5 (476.1)aMean (S.D.) 522.7 (728) 296.2 (344.9) Range 0 – 5,263 0 – 2,106 -3,156.6 - 578 Counties with no PCP provider 24 27 3

a p<0.001


Table 6: Border and Non-Border Counties

1990 2000 Difference

PCP/100,000 GP/FP/IM/PD Border Non-Border

37.9 (23.6) 43.9 (25.2)

37 (21.1) 42.3 (24.5)

-0.9 (15.3) -1.6 (22.6)

Pediatric FTEs/100,000 age less than 18 Border Non-Border

38.8 (29.9) 52.9 (34.3)a

40.1 (25.7) 50.6 (33.2)b

-1.3 (22.9) 2.6% -2.3 (30.8) -3.8%

PCP/100,000 elderly Border Non-Border

286.1 (157.8)

289.1 (203.3) 255.5 (137.6) 277.4 (189)

-30.6 (117.9)-10.8%c

-11.7 (164.1) -4.2% PCP/100,000 Hispanics Border Non-Border

86.1 (119.9) 611.7 (767.3)e

73.4 (84.5) 341.7 (360.7)e

-12.7 (75.5) -1.2% -270 (511)d -41.2%

Rural Urban PCP/100,000 Comparisons: Rural Border 35.6 (24.1) 34.2 (20.5) -1.4 (16.5) -3.9%

40.5 (24.5) Rural Non-Border 41.7 (25.1) -1.2 (25.2) -2.9% a. Border versus Non-Border 1990, p=0.013 b. Border versus Non-Border 2000, p=0.024 c. Border 1990 versus 2000, p=0.096 d. Non-Border 1990 versus 2000, p<0.001 e. Border versus Non-Border 1990&2000, p<0.001


Table 7: Rural/Urban PCP/100,000 Comparisons

1990 2000 Difference Mean number of PCP per County Rural Urban

6.6 (7.4)

160.6 (373.5)a

7.2 (7.9)

181.1 (383.1)b

.6 (2.8)c

20.5 (38.8)d

PCP/100,000 Rural Urban

40.6 (25)

50.6 (23.6)e

39.3 (23.9) 48.4 (23)f

-1.3 (23.8) -2% -2.2 (10.7) -3%

Pediatric FTE/100,000 less than age 18 Rural Urban

47.4 (34.2) 61.1 (30.9)g

45.6 (32.3) 59.7 (29.8)h

-1.8 (32.5) -1.4 (16.9)

PCP/100,000 elderly Rural Urban

247.7 (174.3) 426.7 (203.6)i

238.7 (161.9) 392.1 (194)j

-9.0 (173)

-34.6 (81.8)k

PCP/100,000 Hispanic

Rural Urban

491.2 (742.5) 629.1 (672.4)

282.6 (357.3) -208.6 (495)l

m342.5 (297.7) -286.6 (403.9)

a. Urban versus Rural 1990 p=0.003 b. Urban versus Rural 2000 p=0.001 c. Rural 1990 versus 2000 p=0.004 d. Urban 1990 versus 2000 p<0.001 e. Urban versus Rural 1990 p=0.007 f. Urban versus Rural 2000 p=0.011 g. Urban versus Rural 1990 p=0.007 h. Urban versus Rural 2000 p=0.003 i. Urban versus Rural 1990 p<0.001 j. Urban versus Rural 2000 p<0.001 k. Urban 1990 versus 2000 p=0.002 l. Urban versus Rural 1990 p<0.001 m. Urban versus Rural 2000 p<0.001


draft: primary care physician and physician assistant

Documents

primary care hpsa

primary care physician

direct patient care

pediatric providers

pcsalevel comparison

comparison of pcsa pcp

comparison of pcsa analysis

obgyn providers