Learning and the "Early Joiner" Effect for Medical Conditions in Medicare's Bundled Payments for Care Improvement Program: Retrospective Cohort Study.

BACKGROUND Studies of medical conditions in the Bundled Payments for Care Improvement (BPCI) initiative did not show reductions in Medicare payments for the majority of conditions, but this could mask heterogeneity. OBJECTIVE To determine whether earlier enrollment and/or longer participation in BPCI were associated with performance. DESIGN We divided BPCI hospitals into wave 1 (joined 10/1/13, 1/1/14, or 4/1/14), wave 2 (joined 7/1/14, 10/1/14, 1/1/15, or 4/1/15), and wave 3 (joined 7/1/15, 10/1/15, or 1/1/16) and compared changes in Medicare payments for acute myocardial infarction, heart failure, pneumonia, sepsis, and chronic obstructive pulmonary disease between BPCI and matched controls in 6-month increments. SUBJECTS US hospitals. MEASURES Medicare payments. RESULTS There were 120 hospital-condition pairs in wave 1, 264 in wave 2, and 300 in wave 3. Wave 1 hospitals had similar savings to controls early in the program (0-6 mo difference in differences -$10, P=0.976; 6-12 mo +$295, P=0.441; 12-18 mo -$540, P=0.218; 18-24 mo -$485, P=0.259) but had greater savings than controls at 24-30 months (difference in differences -$663, P=0.035). Wave 2 (0-6 mo +$193, P=0.524; 6-12 mo -$183, P=0.489; 12-18 mo -$162, P=0.618) and wave 3 hospitals (0-6 mo +$79, P=0.753; 6-12 mo -$32, P=0.876) did not achieve significant savings at any time interval. There were no differential changes in patient outcomes over time. CONCLUSIONS Hospitals that joined BPCI earliest began to achieve savings at roughly 2 years of participation. These findings have implications for this and other alternative payment models.