People with Long COVID Are at Higher Risk of Early Death and Disease

In a new study published in JAMA Health Forum, people with Long COVID had an increased risk of dying during the study period and developing serious health problems compared to people who never had COVID-19.

Long COVID is an umbrella term for health issues that emerge during or after a case of COVID-19 and last weeks, months, or longer. Some symptoms—like fatigue, cognitive dysfunction, and chronic pain—affect patients’ daily lives, while others—like organ damage—linger beneath the surface, potentially causing serious illness later on. The new study looks at the latter.

The researchers drew from a database that includes health-record data for millions of people in the U.S. covered by 14 commercial insurance plans. Using those records, they examined a group of about 13,500 U.S. adults who were diagnosed with COVID-19 from April to July 2020 and went on to develop Long COVID. Almost 27,000 adults who had no COVID-19 diagnosis during the study period but were similarly matched in terms of demographics and pre-pandemic health status served as a control group. (The rate of preexisting conditions was fairly high among both groups, the authors note, but they accounted for overall health in their analysis.)

In the year after their COVID-19 diagnoses, people with Long COVID were significantly more likely to seek care for health problems including irregular heartbeats, blood clots, strokes, heart disease, heart failure, and respiratory disease, compared to the control group. Irregular heartbeats and chronic obstructive pulmonary disease (COPD) were the most commonly treated conditions among people with Long COVID, with about 30% of the group seeking care for each. Only 12.5% and 16.5% of controls, meanwhile, sought care for irregular heartbeats and COPD, respectively.

Read More: How COVID-19 Changes the Heart—Even After the Virus Is Gone

People who were hospitalized with COVID-19 when they first got sick were especially likely to later have health problems. Among that group, more than half got treatment for irregular heartbeats, more than 40% got treatment for COPD, and almost 30% got treatment for heart disease.

More people with Long COVID also died during the follow-up period: almost 3% of the people with Long COVID died in the year after their initial COVID-19 cases, compared to just over 1% of the people who hadn’t been diagnosed with COVID-19.

There are a few caveats to the research. First, health records aren’t a perfect data source because they only include people who sought medical care, which excludes people who either didn’t have access or were well enough to manage their symptoms at home; health records also may not reflect every symptom someone experiences. Second, the study looked at people who got COVID-19 in 2020, before vaccines were available. While vaccines do not entirely prevent Long COVID, they reduce the risk of developing it. Finally, it’s possible that some people in the control group had COVID-19 and didn’t know it.

Even with those caveats, the study adds more support to an increasingly solid conclusion: COVID-19 leaves its mark on the body in myriad ways, some of which last far longer—and are more serious—than a few days of flu-like symptoms.

Write to Jamie Ducharme at jamie.ducharme@time.com.