the impact of volume of outpatient surgical procedures on quality outcomes: 1997-2004
DESCRIPTION
The Impact of Volume of Outpatient Surgical Procedures on Quality Outcomes: 1997-2004. AcademyHealth: June 4, 2007. Research Team. Askar Chukmaitov, M.D., Ph.D. Nir Menachemi, Ph.D., M.P.H. Steven Brown, M.S. Charles Saunders, Ph.D. Robert Brooks, M.D., M.B.A. - PowerPoint PPT PresentationTRANSCRIPT
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The Impact of Volume of Outpatient Surgical Procedures on Quality
Outcomes: 1997-2004
AcademyHealth: June 4, 2007
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Research Team
Askar Chukmaitov, M.D., Ph.D. Nir Menachemi, Ph.D., M.P.H. Steven Brown, M.S. Charles Saunders, Ph.D. Robert Brooks, M.D., M.B.A.
Funding support from the Florida Agency for Health Care Administration (AHCA)
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Inverse relationship between hospital/surgical volume and adverse patient outcomes in inpatient settings
Better outcomes for high-volume hospitals and high-volume surgeons
Lack of research on volume-quality relationship in outpatient surgical settings
Important issue, because:
60-70% of all surgeries are performed now in outpatient settings
Medicare payment for outpatient procedures has doubled over the
last decade
Rationale for the Study
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Methods
Design– Longitudinal analysis of 1997-2004 data
Data– Ambulatory discharge, hospital discharge, vital statistics
Sampling– Colonoscopies (n=2,820,769), Cataracts (n=2,058,090), and
upper gastrointestinal endoscopies (n=1,348,121) in ASCs and HOPDs
Analytical Approach Physician volume and patient outcomes (Model 1) Outpatient facility volume and patient outcomes (Model 2) Combined surgeon and facility volume and patient
outcomes (Model 3) Controls: Patient severity, age, gender, payer type, location
of care, time fixed effects, and clustering of outcomes
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Key Variables
Adverse patient outcomes– 7- and 30-day unexpected hospitalization– 7- and 30-day mortality
Physician and Facility Volume – Ranked providers according to volume tertiles:
low (<34%), medium (34-67%) and high (>67%, the reference group)
Patient Severity/Risk Adjustment – Relative Risk Scores calculated using DCG/HCC
methodology
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Physicians: 2,857 Facilities: 874 (ASC=61.64%) Unexpected Hospitalizations less than 5% Mortality Rates less than 1% Patient demographics
– Age: 65.62 (sd=14.26)– Female: 57.3%– White: 76.79%– Severity risk score: 0.89 (sd=0.82)– Private-pay: 25.92%– Medicare: 54.56%– Medicaid: 1.95% – HMO: 13.42%
Results – Descriptive
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7-day Unexpected Hospitalizations after Colonoscopies
Controlled for patient severity, age, gender, payer type, location of care, time fixed effects, and clustering of outcomes
*p<.05 **p<.01 ***p<.001
Volume Category Odds Ratio (95% CI)
Tertile 3 - High 1.00
Tertile 2 - Medium 1.24 (1.13 – 1.37)*** Model 1:
Physician Volume Only Tertile 1 - Low 1.42 (1.25 – 1.61)***
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7-day Unexpected Hospitalizations after Colonoscopies
Controlled for patient severity, age, gender, payer type, location of care, time fixed effects, and clustering of outcomes
Volume Category Odds Ratio (95% CI)
Tertile 3 - High 1.00
Tertile 2 - Medium 1.24 (1.13 – 1.37)*** Model 1:
Physician Volume Only Tertile 1 - Low 1.42 (1.25 – 1.61)***
Tertile 3 - High 1.00 Tertile 2 - Medium 1.09 (1.01 – 1.17)*
Model 2: Facility
Volume Only Tertile 1 - Low 1.22 (1.19 – 1.32)*** *p<.05 **p<.01 ***p<.001
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7-day Unexpected Hospitalizations after Colonoscopies
Controlled for patient severity, age, gender, payer type, location of care, time fixed effects, and clustering of outcomes
Volume Category Odds Ratio (95% CI) Tertile 3 - High 1.00 Tertile 2 - Medium 1.23 (1.11 – 1.35) ***
Model 3: Physician Volume
Tertile 1 - Low 1.38 (1.21 – 1.57) *** Tertile 3 - High 1.00 Tertile 2 - Medium 1.06 (0.98 – 1.14) Facility Volume Tertile 1 - Low 1.12 (1.02 – 1.23)*
Physician vs. Facility Tertile 2 χ2 = 5.1 *
The Wald Test Physician vs. Facility Tertile 1 χ2 = 5.4 *
*p<.05 **p<.01 ***p<.001
Patterns in 7- and 30-day Mortality Outcomes by Volume Category (1997-2004)
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colonoscopy, 7 day
colonoscopy, 30 day
cataract, 7 day
cataract, 30 day
gastrointestinalendoscopy, 7 day
gastrointestinalendoscopy, 30 day
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Consistent, dose-responsive, inverse relationship between volume and outcomes for unexpected hospitalization
Physician volume demonstrated stronger effects than facility volume
In terms of mortality, a similar pattern was noted. The lack of statistically significant findings may be due to the rarity of deaths
Conclusions
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Significance to Policy
Further research is needed to validate these findings with data from other states, using different outcome measures, risk adjustment techniques, and analytical approaches
Volume of outpatient surgical procedures may indicate improved provider skills and processes of care delivery
Possible development of outpatient standards/guidelines (e.g., Leap Frog)
Volume-based outpatient referrals should be considered by patients, providers, payers, and policy-makers