Guest editorial

Optimal management improves asthmamorbidity and mortality

Rates of death from asthma in the United States increasedfrom 1978 until 1988, but then tended to stabilize and mayhave decreased since then.1–3 Implementation in 1999 of thetenth revision of the International Classification of Diseases(ICD) has hampered interpretation of the most recent trends.Death certificates that listed both asthma and chronic obstruc-tive pulmonary disease were assigned to asthma in the ninthrevision but to “other chronic lower respiratory diseases” inICD-10.4 The comparability ratio for asthma for ICD-10 ascompared with ICD-9 based upon double-coding of a largesample of 1996 death certificates is 0.8938; nearly 11% fewerdeaths are coded to asthma by ICD-10. The rate of death fromasthma in 1999 (J45-J46) was 1.7 per 100,000 general pop-ulation, somewhat less than 2.0 per 100,000 in 1997 and 1998(493, ICD-9) even after adjustment for the comparabilityratio.1,4 Nevertheless, conclusive establishment of a decreas-ing trend awaits data from subsequent years.Rates of death from asthma have remained much higher for

blacks than whites and higher for women than men (Table 1).5Self-reported prevalence of asthma in the United States

may have peaked in 1995 at 55.2 per 1,000 as estimated fromannual national Health Interview Surveys.2 A change in col-lection of data in 1997 has limited interpretation of trends inprevalence. Previously interviewers asked participants in thenational probability sample whether they had had asthmaduring the previous 12 months. In 1997 they started to ask,“Has a doctor or other health professional ever told you thatyou had asthma? During the past 12 months have you had anepisode of asthma or an asthma attack?” Prevalence ofasthma increased from 31.4 per 1,000 general population in1980 to 55.2 in 1995 and decreased slightly to 54.6 in 1996.2Self-reported lifetime prevalence in 1997 was 96.6 per 1,000population, but current physician-diagnosed prevalence was40.7 per 1,000. Current prevalence decreased to 38.4 in 1999.Prevalence has been higher among blacks than whites, higheramong females than males, and highest at 5 to 14 years of age(Table 2).2 There had been little change in prevalence of acuteasthma among children and adolescents from 1997 through2000.3Measures of morbidity include numbers of admission to

the hospital for asthma. Overall rates of hospitalization forasthma in the United States peaked from 1982 to 1986 andhave decreased since then as estimated by National HospitalDischarge Surveys, although rates in the West have increasedthrough 1999.2 Rates have been much higher for blacks than

whites, higher for females than males, and highest at �5years of age (Table 3).2 Rates of hospitalization for asthmaamong children �5 years of age and 5 through 10 years ofage peaked in 1995 to 1996 and have subsequently de-creased.3Ng et al6 report decreases in rates of admission to the

hospital for asthma in Singapore from 21.7 per 10,000 in1991 to 15.4 per 10,000 in 1998, rates quite similar to thoseobserved in the United States over the same period. Rateswere much higher overall for minorities (32.8 per 10,000 forMalays and 40.8 for Indians) than for Chinese (11.9 per10,000). The authors indicate the population of Singapore is77% Chinese. They have previously reported that asthmamortality rates in Singapore have been much higher forMalays and Indians than for Chinese.7Another measure of morbidity is the number of emergency

department visits for asthma as estimated in the United Statesfrom the National Hospital Ambulatory Medical Care Sur-vey. From 1992 to 1999 rates of emergency department visitswith asthma as the first-listed diagnosis increased 29%. Rateswere much higher for blacks than whites, somewhat higherfor females than males, and highest for children �5 years ofage (Table 4).2Rates of visits for asthma to physicians’ offices and hos-

pital outpatient departments increased through 1998 but de-creased in 1999.2The average number of school days missed because of

asthma among asthmatic children as estimated from NationalHealth Interview Surveys did not change significantly from1980 to 1982 (4.9 days) through 1994 to 1996 (3.7 days), andabsenteeism from work attributable to asthma was stable (2.4days in 1980 to 1982, 2.5 days in 1994 to 1996).2Most of these data indicate some improvement in asthma

morbidity as well as mortality in the United States, consistentwith improvement in other countries.6,8–14Although there is some evidence that diagnostic transfer

may have accounted for some of the apparent changes atextremes of age,3 this is not likely to have had any substantialeffect on trends at 5 to 64 years of age, where accuracy ofdiagnosis of asthma has been highest.Neither emergency department visits nor rates of admis-

sion to hospitals are sensitive indicators of morbidity.Changes in indications for admission can result in stable ordecreasing rates of hospitalization despite increased severityof asthma.15 In the absence of any nationally accepted or

10 ANNALS OF ALLERGY, ASTHMA, & IMMUNOLOGY

widely applied standards for admission that may havechanged, national data such as these are reasonable indicatorsof morbidity trends.Improved management of asthma is the most likely expla-

nation for decreased morbidity and stabilization or decreases

in mortality.1 Increasing use of inhaled corticosteroids hasbeen associated with improved morbidity and mortality in theUnited States,16,17 as well as other countries.18–20Disparities in management of asthma among minorities

remain a matter of concern in the United States21–24 andelsewhere.6,7,11 Whether such differences may be attributablelargely to differences in access to care or financial or culturalbarriers to care remains unknown.

R. MICHAEL SLY, MDSection of Allergy and ImmunologyChildren’s National Medical CenterandProfessor of PediatricsThe George Washington University Schoolof Medicine and Health SciencesWashington, DC

REFERENCES1. Sly RM. Decreases in asthma mortality in the United States.Ann Allergy Asthma Immunol 2000;85:121–127.

2. Mannino DM, Homa DM, Akinbami LJ, et al. Surveillance forasthma–United States, 1980–1999. MMWR Surveill Summ2002;51:1–13.

3. Akinbami LJ, Schoendorf KC. Trends in childhood asthma:prevalence, health care utilization, and mortality. Pediatrics2002;110:315–322.

4. Anderson RN, Miniaeo AM, Hoyert DL, Rosenberg HM. Com-parability of cause of death between ICD-9 and ICD-10: pre-liminary estimates. Natl Vital Stat Rep 2001;49:1–38.

5. Hoyert DL, Arias E, Smith BL, et al. Deaths: final data for1999. Natl Vital Stat Rep 2001;49:1–113.

6. Ng TP, Niti M, Tan WC. Trends and ethnic differences inasthma hospitalization rates in Singapore, 1991 to 1998. AnnAllergy Asthma Immunol 2003;90:51–55.

7. Ng TP, Tan WC. Temporal trends and ethnic variations inasthma mortality in Singapore, 1976–1995. Thorax 1999;54:990–994.

Table 1. Rates of Death from Asthma per 100,000 GeneralPopulation (J45–J46), United States, 1999

All races 1.7Male 1.2Female 2.2

Caucasian 1.5Male 0.9Female 2.0

African-American 3.3Male 2.9Female 3.6

Table 2. Estimated Annual Prevalence per 1,000 Population of anEpisode of Asthma during the Previous 12 Months by Race, Sex,and Age, United States

1997 1999

Race:Caucasian 40.5 37.6African-American 45.4 38.9

Sex:Male 33.0 31.6Female 47.9 44.5

Age group (years)0–4 41.2 42.15–14 60.0 56.415–34 44.2 42.235–64 37.0 33.465� 27.3 22.1

Taken from the National Health Interview Surveys.2

Table 3. Estimated Annual Rates of Hospitalization for Asthma asFirst-Listed Diagnosis per 10,000 General Population by Race, Sex,and Age Group, United States, 1980–1999

1980 1985 1990 1995 1999

RaceCaucasian 15.6 15.8 12.6 11.8 10.6African-American 27.0 31.1 38.3 40.7 35.6

SexMale 17.4 17.4 15.6 16.1 14.1Female 20.3 22.2 22.1 22.4 20.6

Age group (years)0–4 37.3 47.8 55.6 62.6 55.45–14 18.1 17.3 18.5 25.0 21.515–34 8.5 9.7 9.4 10.2 10.135–64 18.9 18.6 15.5 15.0 13.465� 32.8 34.4 33.0 23.5 21.1

Total* 19.0 19.7 19.2 19.5 17.6

* Age-adjusted to 2000 US population.Taken from National Hospital Discharge Surveys.2

Table 4. Estimated Annual Rates of Emergency Department Visitsfor Asthma as the First-Listed Diagnosis per 10,000 Population byRace, Sex, and Age Group, United States, 1992–1999

1992 1995 1999

RaceCaucasian 43.7 46.9 59.4African-American 143.2 226.4 174.3

SexMale 51.7 54.4 68.6Female 61.5 85.9 77.2

Age group (years):0–4 153.0 131.2 141.85–14 80.6 85.8 98.515–34 55.3 72.7 81.335–64 41.0 66.5 58.165� 28.0 28.7 35.5

Total* 56.8 70.7 73.3

* Age-adjusted to 2000 US population.Taken from National Hospital Ambulatory Medical Care Survey.2

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8. Sly RM, O’Donnell R. Stabilization of asthma mortality. AnnAllergy Asthma Immunol 1997;78:347–354.

9. Jorgensen IM, Bulow S, Jensen VB, et al. Asthma mortality inDanish children and young adults, 1973–1994: epidemiologyand validity of death certificates. Eur Respir J 2000;15:844–848.

10. Morrison DS, McLoone P. Changing patterns of hospital ad-mission for asthma, 1981–97. Thorax 2001;56:687–690.

11. Ellison-Loschmann L, Cheng S, Pearce N. Time trends andseasonal patterns of asthma deaths and hospitalisations amongMaori and non-Maori. N Z Med J 2002;115:6–9.

12. Tanihara S, Nakamura Y, Oki I, et al. Trends in asthma mor-bidity and mortality in Japan between 1984 and 1996. J Epide-miol 2002;12:217–222.

13. Soler M. Trends in asthma mortality in Italy and Spain,1980–1996. Eur J Epidemiol 2001;17:545–549.

14. Connolly CK, Alcock SM, Prescott RJ. Mortality in asthmaticsover 15 years: a dynamic cohort study from 1983–1998. EurRespir J 2002;19:593–598.

15. Russo MJ, McConnochie KM, McBride JT, et al. Increase inadmission threshold explains stable asthma hospitalizationrates. Pediatrics 1999;104:454–462.

16. Sly RM. Changing asthma mortality and sales of inhaled bron-chodilators and anti-asthmatic drugs. Ann Allergy 1994;73:

439–443.17. Terr AI, Bloch DA. Trends in asthma therapy in the United

States:1965–1992. Ann Allergy Asthma Immunol 1996;76:273–281.

18. Keating G, Mitchell EA, Jackson R, et al. Trends in sales ofdrugs for asthma in New Zealand, Australia, and the UnitedKingdom, 1975–81. BMJ (Clin Res Ed) 1984;289:348–351.

19. Haas JF, Staudinger HW, Schuijt C. Asthma deaths in NewZealand [letter]. BMJ 1992;304:1634.

20. Comino E, Henry R. Changing approaches to asthma manage-ment in Australia: effects on asthma morbidity. Drugs 2001;61:1289–1300.

21. Diaz T, Sturm T, Matte T, et al. Medication use among childrenwith asthma in East Harlem. Pediatrics 2000;105:1188–1193.

22. Rand CS, Butz AM, Kolodner K, et al. Emergency departmentvisits by urban African American children with asthma. J Al-lergy Clin Immunol 2000;105:83–90.

23. Halterman JS, Aligne CA, Auinger P, et al. Inadequate therapyfor asthma among children in the United States. Pediatrics2000;105:272–276.

24. Lieu TA, Lozano P, Finkelstein JA, et al. Racial/ethnic variationin asthma status and management practices among children inmanaged Medicaid. Pediatrics 2002;109:857–865.

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