The Comprehensive Primary Care Plus Model and Health Care Spending, Service Use, and Quality

IMPORTANCE: Implemented in 18 regions, Comprehensive Primary Care Plus (CPC+) was the largest US primary care delivery model ever tested. Understanding its association with health outcomes is critical in designing future transformation models. OBJECTIVE: To test whether CPC+ was associated with lower health care spending and utilization and improved quality of care. DESIGN, SETTING, AND PARTICIPANTS: Difference-in-differences regression models compared changes in outcomes between the year before CPC+ and 5 intervention years for Medicare fee-for-service beneficiaries attributed to CPC+ and comparison practices. Participants included 1373 track 1 (1 549 585 beneficiaries) and 1515 track 2 (5 347 499 beneficiaries) primary care practices that applied to start CPC+ in 2017 and met minimum care delivery and other eligibility requirements. Comparison groups included 5243 track 1 (5 347 499 beneficiaries) and 3783 track 2 (4 507 499 beneficiaries) practices, matched, and weighted to have similar beneficiary-, practice-, and market-level characteristics as CPC+ practices. INTERVENTIONS: Two-track design involving enhanced (higher for track 2) and alternative payments (track 2 only), care delivery requirements (greater for track 2), data feedback, learning, and health information technology support. MAIN OUTCOMES AND MEASURES: The prespecified primary outcome was annualized Medicare Part A and B expenditures per beneficiary per month (PBPM). Secondary outcomes included expenditure categories, utilization (eg, hospitalizations), and claims-based quality-of-care process and outcome measures (eg, recommended tests for patients with diabetes and unplanned readmissions). RESULTS: Among the CPC+ patients, 5% were Black, 3% were Hispanic, 87% were White, and 5% were of other races (including Asian/Other Pacific Islander and American Indian); 85% of CPC+ patients were older than 65 years and 58% were female. CPC+ was associated with no discernible changes in the total expenditures (track 1: $1.1 PBPM [90% CI, –$4.3 to $6.6], P = .74; track 2: $1.3 [90% CI, −$5 to $7.7], P = .73), and with increases in expenditures including enhanced payments (track 1: $13 [90% CI, $7 to $18], P