June 3, 2020

The weekly number of patients admitted to Kaiser Permanente Northern California (KPNC) hospitals with acute myocardial infarction (heart attacks) after the onset of the COVID-19 pandemic fell to nearly half of what would be expected, new research by Kaiser Permanente shows.

This is the first known population-based study in the U.S. to estimate changes in heart attack hospitalization rates during the new coronavirus pandemic. The findings were reported in a Research Letter published May 19 in the New England Journal of Medicine.

photo of Matthew Solomon, MD, PhD

Matthew Solomon, MD, PhD, cardiologist, The Permenente Medical Group

“Both elderly patients and those who had previously been diagnosed with heart disease repeatedly heard they were high risk for COVID-19,” said lead author Matthew Solomon, MD, PhD, a cardiologist at The Permanente Medical Group and a physician researcher at the Kaiser Permanente Northern California Division of Research. “We worry that our findings suggest these high-risk patients might have stayed home despite having concerning symptoms.”

The researchers reviewed electronic medical records to identify the number of adults admitted to KPNC hospitals with a heart attack during the pre-COVID-19 period of January 1 through March 3, 2020, and the post-COVID-19 period of March 4 through April 14, 2020. The analyses showed that weekly admission rates for heart attacks declined by about half, from an average of 4.1 per 100,000 person weeks ­from January 1 through March 3, to 2.1 per 100,000 person weeks by April 14.

“Admissions for heart attacks started falling right after the time of the first reported death in California from COVID-19 on March 4 and continued to fall dramatically until they were nearly 50% lower by mid-April,” said Solomon.

Additional analyses showed that the heart attack hospitalization rate from March 4 through April 14, 2020, was also markedly lower than what was seen in KPNC hospitals during the same time period in 2019.

The findings support anecdotal reports of physicians seeing fewer patients with acute medical conditions, including heart attacks.

photo of Alan Go, MD

Alan Go, MD, research scientist, Kaiser Permanente Division of Research

“Given how the COVID-19 pandemic and our societal response has been changing so quickly, it was important for us to let medical providers and governments know as rapidly as possible that the experiences physicians were reporting were true at the population level,” said senior author Alan Go, MD, associate director overseeing cardiovascular and metabolic research at the Kaiser Permanente Northern California Division of Research.

The declines were seen for both very severe and more mild heart attacks. The less severe type of heart attack, known as NSTEMIs (non-ST-elevation myocardial infarction), are 4 to 5 times more common. They are less likely to result in death but can cause long-term heart problems.

“Patients who survive a heart attack but do not seek medical care are at risk for certain medical complications,” added Go. “These complications can include developing new or worsening heart failure, having a repeat heart attack, as well as experiencing dangerous heart rhythms — all of which could increase the risk of dying.”

The researchers say their findings underscore the need to educate the public that it is critical to seek emergency care, even during a pandemic. “The message is clear,” said Solomon. “If you have symptoms of a heart attack or any other health emergency, you must call 911 and be evaluated. We are here to take care of you, our hospitals are safe, and we want to help you get the care you need.”

The study was sponsored by a grant from The Permanente Medical Group Delivery Science and Applied Research and Physician Researcher programs.

Coauthors also include Edward McNulty, MD, and Jamal S. Rana, MD, PHD, both of The Permanente Medical Group, and Thomas K. Leong, MPH, Catherine Lee, PhD, Sue Hee Sung, MPH, Andrew P. Ambrosy, MD, and Stephen Sidney, MD, MPH, of the Kaiser Permanente Northern California Division of Research.

This story originally appeared in KP Research Spotlight