Context: Physicians have increasingly become the focus of clinical performance measurement.
Objective: To investigate the relationship between patient panel characteristics and relative physician clinical performance rankings within a large academic primary care network.
Design, setting, and participants: Cohort study using data from 125,303 adult patients who had visited any of the 9 hospital-affiliated practices or 4 community health centers between January 1, 2003, and December 31, 2005, (162 primary care physicians in 1 physician organization linked by a common electronic medical record system in Eastern Massachusetts) to determine changes in physician quality ranking based on an aggregate of Health Plan Employer and Data Information Set (HEDIS) measures after adjusting for practice site, visit frequency, and patient panel characteristics.
Main outcome measures: Composite physician clinical performance score based on 9 HEDIS quality measures (reported by percentile, with lower scores indicating higher quality).
Results: Patients of primary care physicians in the top quality performance tertile compared with patients of primary care physicians in the bottom quality tertile were older (51.1 years [95% confidence interval {CI}, 49.6-52.6 years] vs 46.6 years [95% CI, 43.8-49.5 years], respectively; P < .001), had a higher number of comorbidities (0.91 [95% CI, 0.83-0.98] vs 0.80 [95% CI, 0.66-0.95]; P = .008), and made more frequent primary care practice visits (71.0% [95% CI, 68.5%-73.5%] vs 61.8% [95% CI, 57.3%-66.3%] with >3 visits/year; P = .003). Top tertile primary care physicians compared with the bottom tertile physicians had fewer minority patients (13.7% [95% CI, 10.6%-16.7%] vs 25.6% [95% CI, 20.2%-31.1%], respectively; P < .001), non-English-speaking patients (3.2% [95% CI, 0.7%-5.6%] vs 10.2% [95% CI, 5.5%-14.9%]; P <.001), and patients with Medicaid coverage or without insurance (9.6% [95% CI, 7.5%-11.7%] vs 17.2% [95% CI, 13.5%-21.0%]; P <.001). After accounting for practice site and visit frequency differences, adjusting for patient panel factors resulted in a relative mean change in physician rankings of 7.6 percentiles (95% CI, 6.6-8.7 percentiles) per primary care physician, with more than one-third (36%) of primary care physicians (59/162) reclassified into different quality tertiles.
Conclusion: Among primary care physicians practicing within the same large academic primary care system, patient panels with greater proportions of underinsured, minority, and non-English-speaking patients were associated with lower quality rankings for primary care physicians.