Do accountable care organizations affect race mediated differences in cancer screening

131Background: Accountable care organizations (ACO) reflect a payment innovation aimed to orient incentives to improve quality and reduce waste. The objective of this study was to determine whether ACO enrollment affects racial disparities in cancer screening, and to characterize the impact on the appropriateness of prostate cancer screening in minority populations. Methods: We built a cohort of Medicare beneficiaries from 2007 to 2013 were comprising a cohort of 11,087,056 person-years among ACO beneficiaries and 37,187,979 person-years among non-ACO beneficiaries. A difference-in-difference-in-differences (DDD) approach was utilized to identify the effect of ACO enrollment on cancer screening in racial/ethnic minorities relative to non-Hispanic whites. We then characterized differences in screening appropriateness after ACO enrollment using age (65-74 vs. 75+) and predicted survival (top vs. bottom quartile). Results: ACO enrollment was associated with approximately a 5% reduction in prostate cancer ove...