By Betsy McKay

The Covid-19 pandemic has driven up death rates for heart disease and strokes in the U.S., a new study demonstrated, widening already significant racial and ethnic disparities in health outcomes.

Mortality rates from heart disease and stroke rose 4.3% and 6.4% respectively in 2020, part of a larger wave of excess deaths in the first year of the pandemic, according to a study published Wednesday. Overall, the U.S. mortality rate jumped 15.9% that year, according to the analysis, which was based on data from the Centers for Disease Control and Prevention.

Heart disease has long been the nation’s leading killer, and stroke is the fifth leading cause of death.

Progress in reducing deaths from both had slowed substantially in the years before the pandemic, after decades of success.

The downward trajectory reversed in 2020, said Stephen Sidney, director of research clinics at the Kaiser Permanente Northern California Division of Research and lead author of the study. The 696,962 recorded deaths from heart disease in 2020 was the highest yearly number since 2002, he said, adding that preliminary CDC data for 2021 are similar. The number of heart-disease deaths overall declined 1% last year to 689,807 and stroke deaths rose 1.2% to 162,140, he said.

“I think it is likely true that 2020 was not a one-year blip,” Dr. Sidney said.

The worsening trend in 2020 was due mostly to a change in risk—likely due to the pandemic—rather than the effect of the aging U.S. population, Dr. Sidney and his co-authors found.

The change in 2020 was greatest among Black people, who have long had the highest mortality rates for these diseases. Increases in deaths attributed to risk rose at least five times as much percentage-wise for non-Hispanic Black people as for non-Hispanic white people. For stroke, risk-related increases in deaths rose twice as much among Black people compared with white people. The increase in deaths due to risk was greater as well for Hispanic and Asian populations.

“That is reflecting badly on our ability to address health disparities,” Dr. Sidney said.

It will take years for researchers to understand the full toll of Covid-19, from damage caused by the disease itself to the effects of the pandemic’s physical and social disruptions on other diseases. Many people were unable or unwilling to visit doctors or hospitals for health concerns other than Covid-19 early in the pandemic. They died at home, or got to hospitals too late. Many people have been under unusual amounts of stress, not as active or haven’t kept up with social and medical routines.

“The pandemic melted the tip of the iceberg to reveal how precarious our healthcare system is” for many populations,” said Jamal Rana, chief of cardiology at Kaiser Permanente Medical Center in Oakland, Calif., and senior author of the study. He said patients who come for care now are much sicker than those before the pandemic.

Doctors need to redouble their efforts to help patients, particularly Black adults, improve their blood pressure and diet as well as manage other risk factors, said Keith Ferdinand, a preventive cardiologist and professor of medicine at Tulane University School of Medicine, who wasn’t involved in the study.

He said he has done his best to keep in contact with his patients, particularly when clinics were closed. Telehealth has helped, he said. Patients also need access to blood pressure devices, he said. He is leading a study to evaluate whether such devices help patients better control their blood pressure.

Some scientists question the accuracy of recent mortality data. They say it will take more time to sort out how many people died of Covid-19 compared with other diseases.

Studies have shown death certificates sometimes list the wrong cause of death. Deaths surged in the past two years, with people passing away both in and out of hospitals. Many were tested for Covid-19; others weren’t because tests weren’t available.

Covid-19 has a range of complications, including inflammation of the heart and other cardiovascular problems. About one-third of deaths attributed to Covid-19 in 2020 list heart disease as a contributing cause, and about 8,900 deaths attributed to heart disease include Covid-19 as a contributor, Dr. Sidney said.

“It is challenging to ascribe cause of death in a pandemic,” said Harlan Krumholz, a Yale University cardiologist and healthcare researcher who wasn’t involved in the study. Still, he said, “a report like this shows and emphasizes the unfortunate truth that we have large-scale disparities in this country.”