The COVID-19 pandemic heralded a 35% drop in hospital admissions for heart attacks in the U.S. — but even now, that rate is continuing to fall. Why?
New research suggests that, although people avoiding medical care during the pandemic contributed to the decline in the short term, better heart-attack prevention is the bigger reason for this downward trend.
A heart attack, or acute myocardial infarction (AMI), happens when there’s a blockage of blood flow to the heart that causes some of the heart’s muscle tissue to die. The symptoms — including chest pain, arm or shoulder pain, shortness of breath, tiredness and nausea — are fairly well known, and most people are aware that heart attacks need immediate medical care in a hospital setting.
However, the pandemic came with an unusual dip in AMI hospitalizations.
Related: Young women may be likelier to die after heart attacks than men
Since 2020, researchers have debated the reasons for this drop. For instance, did patients who were experiencing heart-attack symptoms avoid medical care? Or did patients who might have otherwise had a heart attack die of COVID-19 first?
To investigate these questions, researchers analyzed 7.5 years of Medicare claims data collected between January 2016 and June 2023. They looked at the rates of AMI-related emergency room visits and hospitalizations and the characteristics of the affected patients.
The study, published July 31 in the journal JAMA Cardiology, found that AMI visits and hospitalizations were lowest when the pandemic was at its peak, as measured by COVID-19 death rates. The same was true for other urgent or painful conditions, such as kidney stones. This suggests that people who normally might have sought care chose to stay home when COVID-19 infection risk was high.
The scientists tried correcting for factors such as excess COVID-19 deaths, meaning those over and above the number of deaths that would be expected under typical conditions. However, that adjustment didn’t explain the drop in hospital visits, so the researchers concluded that care avoidance was the main cause of the pandemic-related reduction.
“Although there were more deaths overall during the pandemic, we have to appreciate that only some of those patients would have had an AMI over the same time period,” said study first author Andrew Wilcock, an assistant professor at the University of Vermont Larner College of Medicine and a visiting fellow at Harvard Medical School.
The effects of excess deaths or changes in Medicare enrollment were “so slight on expected [AMI] rates that they could not explain the shortfalls we observed,” Wilcock told Live Science in an email.
But even after pandemic-related restrictions were lifted, AMI visits and hospitalizations stayed lower than they had been before the pandemic. This reflects a broader and sustained decline in heart-attack rates. The researchers propose a combination of reasons for this trend, including that fewer people are smoking, people may be eating healthier, and there is better treatment for underlying conditions such as high cholesterol and high blood pressure.
“It’s not just one thing, but a constellation of factors,” Wilcock said. “Lifestyle changes and better drugs are compelling explanations for the downward trend in AMI hospitalizations.”
There’s still room for progress, though.
“We’ve made improvements, but we still have a lot to do in terms of smoking cessation, exercise, diet, blood pressure and cholesterol control, and so forth,” said Dr. Robert Bonow, a professor of cardiology at Northwestern University who was not involved in the research. “Cardiovascular disease remains the leading cause of death worldwide. It would be nice to see it drop to number two.”
The study authors noted that their research had some limitations. For instance, using Medicare claims meant that most of the data came from people with disabilities or chronic illnesses, or who were 65 or older. As a result, AMIs in younger people or those with different health care coverage weren’t included in the numbers.
In addition, the authors noted that they lacked data on patients’ longer-term outcomes. For example, they can’t say whether the drop in AMI-related health care visits at the height of the pandemic led to higher rates of heart attack-related disabilities down the line.
“Although AMIs returned to their expected trends, overall hospitalization incidence hasn’t returned to pre-pandemic levels,” Wilcock said. “The new, post-pandemic normal in use of the hospital is something we would like to understand better.”
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