Risk of rehospitalization in younger women after heart attack nearly double that of men

 NIH-supported findings identify risk factors in women and suggest need for closer monitoring

Women aged 55 years and younger have nearly double the risk of rehospitalization in the year immediately after a heart attack compared to men of similar age, according to a study supported by the National Institutes of Health. Higher rates of risk factors such as obesity, heart failure, and depression among women most likely contributed to the disparity.

The findings suggest a need for closer health monitoring of the approximately 40,000 American women aged 18 to 55 years who have heart attacks each year following hospital discharge, and a better understanding of the reasons behind the different outcomes. The study, funded by the National Heart, Lung, and Blood Institute (NHLBI), part of NIH, was published today in the Journal of the American College of Cardiology.

“We have shown for the first time that rehospitalizations following heart attacks in women aged 55 and younger are accompanied by certain non-cardiac factors, such as depression and low-income, that appear more common in women than men and are associated with more adverse outcomes,” said corresponding author Harlan M. Krumholz, M.D., a cardiologist and professor of medicine at the Yale School of Medicine, New Haven, Connecticut. He is also the director of the school’s Center for Outcomes Research and Evaluation (CORE). “The study reveals a need for paying greater attention to these non-cardiac risk factors in younger women in order help design better clinical interventions and improve outcomes after discharge for a heart attack.”

“Further study of these risk factors could allow doctors and their patients to focus on ways to help improve a woman’s health after hospital discharge,” said Yuan Lu, Sc.D., principal investigator of the study, an investigator at CORE, and an assistant professor at Yale School of Medicine.

Researchers have known for some time that women aged 55 years and younger have about twice the risk of in-hospital death from a heart attack than similarly aged men. However, it was unclear whether women also experience a higher risk of cardiovascular and non-cardiovascular complications a year after leaving the hospital following treatment for a heart attack.

To know more, researchers analyzed data from the NHLBI’s VIRGO (Variation in Recovery: Role of Gender on Outcomes of Young AMI Patients) study, which looks at a broad range of risk factors related to outcomes among women and men who have had heart attacks. The study included 2,979 patients – 2,007 women and 972 men – at 103 U.S. hospitals. The participants were an average age of 48 years and from ethnically and racially diverse populations.

The analysis showed that nearly 30% of these patients were rehospitalized in the year after first leaving the hospital following a heart attack. Most of those re-visits peaked within the first month of a patient’s discharge, then slowly declined in subsequent months. The researchers found that women had nearly twice the risk (1.65 times higher risk) of rehospitalization than men.

For men and women, coronary-related complications — those such as heart attacks and angina that are related to blood vessel blockage – were the leading cause of rehospitalization. Yet, the rate of coronary-related complications for women was nearly 1.5 times higher than that of men – driven in large part by risk factors such as obesity and diabetes.

The biggest sex disparities showed up in non-cardiac rehospitalizations, which were more than twice as high (or 2.10 times higher) in women than men. These were hospitalizations caused by events not related to heart disease or stroke, such as digestive problems, depression, bleeding, and pneumonia. 

The reasons behind these higher non-cardiac rates are unclear, but the researchers found a higher percentage of women than men tended to identify as low income (48% vs 31%) and had a higher history of depression (49% vs 24%). While low income is not a medical measure, it is often associated with poor health status due to limited access to healthcare. The risk for depression is known to increase following a heart attack and may be a risk factor in higher hospitalization rates due in part to undertreatment of the condition in women. However, further studies will be needed to further explore how these factors affect disparate hospitalizations following a heart attack.

“Future research on non-cardiac risk factors after hospital discharge following heart attack could lead to the development of targeted strategies that can narrow this equity gap,” said Gina S. Wei, M.D., MPH, associate director of NHLBI’s Division of Cardiovascular Sciences and NHLBI’s senior scientific advisor on women’s health. “We look forward to more studies in this area.”

This study was supported by grant R01HL081153 from the National Heart, Lung, and Blood Institute and used data from the VIRGO study (NCT00597922).

Study: Sex Difference in Outcomes of Acute Myocardial Infarction in Young Patients. Journal of the American College of Cardiology. doi: 10.1016/j.jacc.2023.03.383