We consider whether hospital acquisitions of physicians lead to improved clinical outcomes for medicare patients aged 65 and older. The analysis combines 2005–2012 Medicare fee-for-service and enrollment data with merger and physician affiliation information from the Levin Reports and SK&A, respectively. We determine the effect of acquisitions on several health outcomes: mortality, acute myocardial infarctions, acute circulatory conditions, ischemic heart disease, glaucoma, symptomatic diabetes complications, and asymptomatic diabetes complications. These outcomes represent the progression of hypertension and diabetes into worse health states. Our results indicate that hospital acquisitions of existing physician practices have little effect on the health outcomes we consider.

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Author notes

We are grateful for helpful comments from Amitabh Chandra and the referee. In addition, we thank Dan Hosken, John McAdams, Luke Olson, Nathan Petek, Elizabeth Schneirov, Devesh Raval, David Schmidt, Bob Town, Christina DePasquale, Brad Shapiro, and audiences at the 2016 ASHE, 2018 ASHE, and 2018 IOS Conferences for helpful comments. Ilana Salant provided excellent research assistance. All remaining errors are our own. The views expressed in this article are those of the authors; they do not necessarily represent those of the Federal Trade Commission or any of its Commissioners.

A supplemental appendix is available online at https://doi.org/10.1162/rest_a_00924.

Supplementary data