Abstract
BACKGROUND: To anticipate the effects of accountable care organizations (ACOs) on surgical care, we examined pre-enrollment utilization, outcomes, and costs of inpatient surgery among hospitals currently enrolled in Medicare ACOs vs nonenrolling facilities. METHODS: Using the Nationwide Inpatient Sample (2007 to 2011), we compared patient and hospital characteristics, distributions of surgical specialty care, and the most common inpatient surgeries performed between ACO-enrolling and nonenrolling hospitals before implementation of Medicare ACOs. We used multivariable regression to compare pre-enrollment inpatient mortality, length of stay (LOS), and costs. RESULTS: Hospitals now participating in Medicare ACO programs were more frequently nonprofit (P < .001) and teaching institutions (P = .01) that performed more specialty procedures (P < .001). We observed no clinically meaningful pre-enrollment differences for inpatient mortality, prolonged length of stay, or costs for procedures performed at ACO-enrolling vs nonenrolling hospitals. CONCLUSIONS: Medicare ACO hospitals had pre-enrollment outcomes that were similar to nonparticipating facilities. Future studies will determine whether ACO participation yields differential changes in surgical quality or costs.