Impact of Medicaid Expansion on Cardiac Surgery Volume and Outcomes

Abstract

Background: Thirty-one states approved Medicaid expansion after implementation of the Affordable Care Act. The objective of this study was to evaluate the effect of Medicaid expansion on cardiac surgery volume and outcomes comparing one state that expanded to one that did not.

Methods: Data from the Virginia (nonexpansion state) Cardiac Services Quality Initiative and the Michigan (expanded Medicaid, April 2014) Society of Thoracic and Cardiovascular Surgeons Quality Collaborative were analyzed to identify uninsured and Medicaid patients undergoing coronary bypass graft or valve operations, or both. Demographics, operative details, predicted risk scores, and morbidity and mortality rates, stratified by state and compared across era (preexpansion: 18 months before vs postexpansion: 18 months after), were analyzed.

Results: In Virginia, there were no differences in volume between eras, whereas in Michigan, there was a significant increase in Medicaid volume (54.4% [558 of 1,026] vs 84.1% [954 of 1,135], p < 0.001) and a corresponding decrease in uninsured volume. In Virginia Medicaid patients, there were no differences in predicted risk of morbidity or mortality or postoperative major morbidities. In Michigan Medicaid patients, a significant decrease in predicted risk of morbidity or mortality (11.9% [8.1% to 20.0%] vs 11.1% [7.7% to 17.9%], p = 0.02) and morbidities (18.3% [102 of 558] vs 13.2% [126 of 954], p = 0.008) was identified. Postexpansion was associated with a decreased risk-adjusted rate of major morbidity (odds ratio, 0.69; 95% confidence interval, 0.51 to 0.91; p = 0.01) in Michigan Medicaid patients.

Conclusions: Medicaid expansion was associated with fewer uninsured cardiac surgery patients and improved predicted risk scores and morbidity rates. In addition to improving health care financing, Medicaid expansion may positively affect patient care and outcomes.