Abstract 18: Aco Payment Models And The Use Of Discretionary And Non-discretionary Cardiovascular Care

Abstract

Background: Accountable care organizations (ACOs) seek to limit discretionary health care spending while ensuring high-quality care. We studied spending patterns in cardiovascular care, one of the largest cost centers for Medicare patients, in hospitals enrolled in an ACO pilot program, the Medicare Physician Group Practice Demonstration (PGPD). Methods: To estimate spending on discretionary and non-discretionary cardiovascular care in for beneficiaries in PGPD and non-PGPD care systems, we performed a quasi-experimental analyses comparing pre-intervention (2001-2004) and post-intervention (2005-2009) rates of use of diagnostic and therapeutic cardiovascular procedures. We studied ten physician groups across the United States. The intervention group was composed of fee-for-service Medicare patients (n=990,177) receiving care from the groups participating in the practices in the PGPD. Controls were Medicare patents (n=7,514,453) from the same regions who received care from non-PGPD physicians. Our main outcome measure was the difference in the rate of discretionary imaging and procedures in PGPD practices compared to control practices, before and after implementation of ACO payment models (difference-in-difference). We studied this for carotid and coronary imaging, in both discretionary and non-discretionary clinical settings. Results: As expected, before and after PGPD implementation, at both PGPD sites and their controls, the rates of carotid and coronary imaging and procedures were higher in non-discretionary situations when compared to discretionary clinical situations (55% versus 22%, p<0.001). For discretionary carotid and coronary imaging, the differences in the rate of change in imaging use before and after the ACO implementation period was minimal (carotid imaging difference between PGPD and controls, 0.25% (95% CI -0.44%-0.95%, discretionary coronary imaging difference between PGPD and controls, 0.06% (95% CI -0.45%-0.58%). Similarly, the differences in the rate of change in discretionary revascularization procedure use before and after ACO implementation was minimal between PGPD sites and controls (carotid revascularization 0.003% 95% CI -0.008%- 0.002%, coronary revascularization -0.13%, 95% CI -0.30% - 0.029%). Similar results were seen for non-discretionary cardiovascular imaging and procedures. Conclusion: Little evidence exists to suggest that ACO payment models will save money by limiting discretionary cardiovascular imaging or procedures.