Composition of generalist physician groups and their performance on medicare’s Merit-based Incentive Payment System (MIPS)

Objective To examine the association between the composition of generalist physician groups by setting specialization and performance on the Medicare Merit-Based Incentive Payment System (MIPS). Methods We conducted a cross-sectional analysis of the 2022 Medicare Physician & Other Practitioners dataset, including 4,145 physician groups composed of general internal medicine, geriatric medicine, or family medicine physicians. Groups were characterized by the percentage of physicians serving multiple settings (i.e., providing > 90% of services in a single setting (hospital, emergency department, office, or nursing home). The primary outcome was the continuous overall MIPS score, with second analyses examining MIPS component scores and whether the score was below the 75-point performance threshold. We used multivariable linear and logistic regression to measure the association between the tiers and MIPS penalty, adjusting for practice characteristics, patient clinical complexity, insurance case mix, and socioeconomic vulnerability. Stratified analyses examined differences by urbanicity. Results Each 10-percentage-point increase in GLSS was associated with a 0.23-point lower overall MIPS score (95% CI: −0.35-−0.11; p < 0.001). Higher GLSS was associated with lower Quality scores (β = −0.46; 95% CI: −0.71-−0.22; p < 0.001), but was not significantly associated with other component scores. In logistic regression, each 10-percentage-point increase in GLSS was associated with 4% higher odds of scoring below the MIPS performance threshold in the fully adjusted model (OR = 1.04; 95% CI, 1.01–1.07; p < 0.01). The association between GLSS and MIPS score was observed among urban groups (β = −0.30; 95% CI: −0.43-−0.17; p < 0.001) but not rural groups (β = 0.08; 95% CI: −0.23–0.40). Conclusions Groups composed of physicians serving multiple settings were more likely to perform poorly on MIPS, with effects associated with drops in the Quality domain and concentrated among urban groups. Future research should evaluate whether this previously understudied aspect of hyper-specialization - setting-based specialization within physician groups - negatively impacts patient outcomes and costs. Clinical trial number Not applicable.