Background: Pay-for-performance programs could worsen health disparities if providers who care for disadvantaged patients face systematic barriers to providing high-quality care. Risk adjustment that includes sociodemographic factors could mitigate the financial incentive to avoid disadvantaged patients.
Objective: To test for associations between quality of care and the composition of a physician's patient panel.
Design: Repeat cross-sectional analysis
Participants: Nationally representative sample of US primary care physicians responding to a panel telephone survey in 2000-2001 and 2004-2005
Main measures: Quality of primary care as measured by provision of eight recommended preventive services (diabetic monitoring [hemoglobin A1c testing, eye examinations, cholesterol testing and urine protein analysis], cancer screening [screening colonoscopy/sigmoidoscopy and mammography], and vaccinations against influenza and pneumococcus) documented in Medicare claims data and the association between quality and the sociodemographic composition of physicians' patient panels.
Key results: Across eight quality measures, physicians' quality of care was not consistently associated with the composition of their patient panel either in a single year or between time periods. For example, a substantial number (seven) of the eighteen significant associations seen between sociodemographic characteristics and the delivery of preventive services in the first time period were no longer seen in the second time period. Among sociodemographic characteristics, panel Medicaid eligibility was most consistently associated with differences in the delivery of preventive services between time points; among preventive services, the delivery of influenza vaccine was most likely to demonstrate disparities in both time points.
Conclusions: In a Medicare pay-for-performance program, a better understanding of the effect of effect of patient panel composition on physicians' quality of care may be necessary before implementing routine statistical adjustment, since the association of quality and sociodemographic composition is small and inconsistent. In addition, we observed improvements between time periods among physicians with varying panel composition.