RESUMEN
BACKGROUND: Medicare Shared Savings Program Accountable Care Organizations (ACOs) may focus more on primary care given ACO financial incentives. We examine variation in primary care treatment of 8 prevalent chronic conditions across ACOs and the factors affecting the variation, and compare the role of primary care in ACOs and non-ACOs. RESEARCH DESIGN: We conduct regression models at the ACO-level to identify factors predicting higher proportions of chronic condition visits delivered by primary care providers (PCPs) using 2013 Medicare claims and enrollment data. We compare the distribution of visits to PCPs, specialists and advanced practice providers between ACO-attributed and non-ACO-attributed beneficiaries. RESULTS: At the ACO-level, the proportion of patients who are white and of the local population who are college educated, the complexity of the patient population, and the supply of specialists were negatively associated with the proportion of chronic condition visits delivered by PCPs, whereas the percentage of contracted physicians within the ACO who were PCPs was positively associated. These results varied when subanalyses were conducted for each specific chronic condition. ACO care for chronic conditions was managed similar to that of care for non-ACO Medicare beneficiaries in 2013, but that some ACOs utilize PCPs to manage chronic conditions more than others. CONCLUSIONS: Many ACOs may underutilize PCPs, and thus could actively shift care to less expensive primary care for potential savings to payers. Barriers to that shift could include low numbers of PCPs contracted in the ACO, and existing referral patterns and patient relationships with specialists.