Physician Behavior in Accountable Care Organizations
Specifically, difference-in-differences style regressions estimate the effects of ACO participation on a series of claims-based process and outcome measures collected from 2009 to 2014. SK&A has collected a unique dataset of public and commercial ACO physician affiliations previously unavailable to researchers. Maintained through a continuously updated phone survey of all U.S. office-based physicians, as of 2014 the data show over 25 percent of all physicians to be participating in either a Medicare or commercial ACO contract. Analyses to date have focused on the effects of Medicare ACO adoption on physician Part B billing summaries for 2012 and 2013 as well as referrals to other providers from 2009 – 2014. “Treatment” metrics developed from billed HCPCS codes include changes in evaluation and management (E&M) visits, diagnostics such as imaging and blood work, and use of invasive surgical procedures.
Preliminary findings indicate that physicians participating in ACOs reduced total billed procedures, with statistically significant decreases in the number of imaging tests and non-new E&M visits. Highlighting potential antitrust concerns surrounding ACOs, preliminary results utilizing public use Medicare physician-to-physician referral data indicate that physicians in Medicare ACOs significantly increased rates of referrals (in terms of both share and total) to members of the same group or system following ACO adoption. Such research is immediately relevant not only to policy makers, but also the patients, providers, and insurers increasingly participating in such arrangements. Findings will inform the ongoing development of both public and commercial ACOs through identification of likely physician responses to changed incentive schemes.