Michigan Heart Surgery Outcomes Improved After Medicaid Expansion, Study Finds

June 7, 2017

Michigan Heart Surgery Outcomes Improved After Medicaid Expansion, Study Finds

University of Virginia

Adapted from a University of Virginia news article

Expanding Medicaid coverage is associated with better outcomes for heart surgery patients, according to a study led by University of Virginia School of Medicine researchers with participation by University of Michigan researchers.

Researchers examined outcomes from heart surgery quality databases in Michigan, which expanded Medicaid under the Healthy Michigan Plan, and Virginia, which did not. Outcomes in both states were reviewed over the same three-year period – the 18 months before Michigan expanded Medicaid in spring 2014, and the first 18 months after Michigan expanded Medicaid. The results are published in the Annals of Thoracic Surgery.

In Virginia, there were no significant changes in outcomes between the two 18-month periods. But among Michigan Medicaid patients, the risk-adjusted likelihood of a serious postoperative complication dropped by 30 percent after Medicaid expansion. Reducing complications may also help reduce the overall costs of care, the researchers said.

The researchers also found that in Michigan, the number of uninsured patients having cardiac surgery dropped by 60 percent, but there was no change in Virginia. The Michigan patients who were still uninsured after Medicaid expansion were older, higher risk, and more likely to die in the month after their operation.  

"An important next step will be to identify patients who did not qualify under traditional Medicaid but gained coverage after expansion and compare them to post-expansion uninsured patients, paying special attention to social determinants of health such as education level, employment status, and housing conditions," the authors write. "This analysis will help determine whether the uninsured actually qualify for expanded Medicaid but have barriers to enrollment or whether they are indeed sicker because they cannot access primary care."

How Medicaid Expansion May Impact Patient Care

Post-expansion Michigan Medicaid patients also had a lower predicted risk of major complications or mortality, which the researchers said might reflect increased access to primary care.

“Once covered, these patients can now access necessary preventative services and primary care, hopefully leading to improved control of chronic medical conditions, such as diabetes and high blood pressure,” said Eric J. Charles, MD, a study co-author and surgical resident at UVA Health System. “This improvement in baseline health status prior to needing an operation may translate into lower preoperative predictive risk scores and subsequently lower postoperative rates of major complications.”

Another possibility, he said, is that patients newly eligible for Medicaid are younger and lower-risk, which could explain the lower risk scores and better outcomes for Michigan patients in the 18 months following Medicaid expansion. An important next step in evaluating the impact of Medicaid expansion, Charles said, would be separate analyses of outcomes for Medicaid patients based on whether they qualified for Medicaid under the traditional criteria or through the expanded criteria.

About the data and the team

The research team involved in the study included partners from the University of Michigan, Inova Heart and Vascular Institute, the Virginia Cardiac Services Quality Institute and the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative.

Both of these efforts contribute data to the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery database. VCSQI consists of 18 cardiac surgery member sites in Virginia, and MSTCVS-QC captures all 33 nonfederal hospitals performing adult cardiac surgery in Michigan.

MSTCVS is led by IHPI member Richard Prager, M.D., a professor of cardiac surgery at the U-M Medical School and co-director of the U-M Frankel Cardiovascular Center.

Donald Likosky, Ph.D., an IHPI member and associate professor of cardiac surgery, is also a co-author. He and Prager and their U-M colleagues are looking further at the impact of Medicaid expansion on a wide range of heart care in Michigan.

Charles and colleagues have described their findings online in The Annals of Thoracic Surgery. The research team consisted of Charles; Lily E. Johnston MD, MPH; Morley A. Herbert PhD; J. Hunter Mehaffey, MD; Kenan W. Yount, MD, MBA; Donald S. Likosky, PhD; Patricia F. Theurer, BSN; Clifford E. Fonner, BA; Jeffrey B. Rich, MD; Alan M. Speir, MD; Gorav Ailawadi, MD; Richard L. Prager, MD; and Irving L. Kron, MD.

The work was supported by the National Heart, Lung and Blood Institute, grants UM1 HL088925 and T32 HL007849; and by the Agency for Healthcare Research and Quality, grant R01 HS022535. Blue Cross and Blue Shield of Michigan and Blue Care Network provide support for the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative.