One in five older adults who undergo heart surgery develops an infection within six months of the procedure, and women are especially at risk, according to two large studies led by Michigan Medicine.
These findings, published in The Journal of Thoracic and Cardiovascular Surgery, shed new light on the long-term risks of common heart surgeries and highlight major disparities in health outcomes.
The research focused on Medicare patients who had either coronary artery bypass grafting (CABG)—a common heart bypass surgery—or aortic valve replacement. These procedures are among the most frequently performed heart surgeries in Michigan and across the United States.
Researchers found that 21.2% of patients developed some kind of infection within six months after surgery. Women had 60% greater odds of getting an infection than men, with the most common types being urinary tract infections (UTIs), pneumonia, and sepsis. Black patients were also more affected than white patients, with an infection rate of 28% compared to 19.2%.
“These results show that disparities in heart surgery outcomes are still a major issue,” said Dr. J’undra N. Pegues, the first author of the study on infection disparities. “It’s clear we need a team-based approach to address both medical and social factors that influence recovery.”
One reason these studies report higher infection rates than earlier ones is the longer follow-up period—six months instead of the more common 30-day tracking window.
According to senior author Dr. Donald Likosky, many infections like UTIs or gastrointestinal problems can appear well after hospital discharge, especially in older adults who often have other health problems like diabetes, high blood pressure, or cancer.
The studies also revealed that not all hospitals perform equally when it comes to preventing infections. Infection rates varied by nearly 40% across different hospitals. Some patients were more likely to be discharged to rehabilitation or extended care facilities, especially if they were treated at hospitals with higher infection rates.
“Monitoring patients for just 30 days doesn’t tell the whole story,” said Dr. Charles Schwartz, co-author and chair of the Department of Surgery at Trinity Health Oakland. “Many important infections go untracked in national registries, which means we may be underestimating how serious the issue really is.”
The findings also show that prevention works. Between 2012 and 2017, Michigan hospitals that joined a statewide program to reduce infections saw success in lowering the rate of pneumonia. These hospitals focused on learning from one another and adopting strategies that could be used across the state.
“The good news is we can make progress,” said Dr. Syed Sikandar Raza, a co-author of the studies. “By bringing hospitals and community groups together, we can share ideas and find ways to reduce infection risks after surgery.”
Heart surgery remains a critical and often life-saving treatment, but this new research shows the need for continued care well after the patient leaves the operating room. It also calls attention to gender and racial differences that must be addressed to ensure safer, more equitable outcomes for all patients.
Ultimately, the studies point to the importance of longer-term follow-up, better hospital practices, and community-based support to protect vulnerable patients—especially older women and Black individuals—who face a higher risk of complications after heart surgery.
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The research findings can be found in The Journal of Thoracic and Cardiovascular Surgery.
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