The potential lasting effects of COVID-19 infection are many — and people with more severe initial infections are at greater risk for long-term complications, according to a study published Thursday in Nature.
The study, thought to be the largest post-acute COVID-19 study to date, sheds more light on the lingering effects of COVID-19 known as "long COVID."
Ziyad Al-Aly and his colleagues used the databases of the U.S. Department of Veterans Affairs to examine health outcomes in more than 73,000 people who'd had COVID-19 and were not hospitalized, comparing them with nearly 5 million users of the VA health system who did not have COVID-19 and were not hospitalized.
Six months later, those who'd had COVID-19 were found to be at higher risk of new onset heart disease, diabetes, mental health disorders including anxiety and depression, substance use disorders, kidney disease and other problems.
Al-Aly, chief of research and development service at the VA St. Louis Health Care System, said it was shocking to see that the toll of long COVID is so substantial and multifaceted.
"We knew people have fatigue, we knew people have weakness, we knew about the memory problems or brain fog," he said. "But when you put it all together, the diabetes and heart problems and kidney problems and liver problems and stroke and brain fog and fatigue and anemia and depression and anxiety — and it's actually quite jarring."
It remains difficult for researchers to distinguish which effects are a direct consequence of the viral infection itself, and which are indirect.
Some consequences could be a result of inflammation provoked by the virus, while others could be linked to life changes that might accompany the disease. "When people get COVID and they have to self-isolate and stay at home in quarantine, maybe that is associated with less physical activity, changes in diet, other changes that might also bring about some of those clinical manifestations," Al-Aly said.
Aftereffects from COVID-19 were seen in the respiratory system, as well as nervous system disorders, mental health problems, metabolic and cardiovascular disorders, malaise, fatigue, musculoskeletal pain and anemia. The authors also found increased use of therapeutics including pain medications (such as opioids), antidepressants, and anti-anxiety medications.
The authors also analyzed the health outcomes of more than 13,600 people who had been hospitalized with COVID-19, and compared them with nearly 14,000 people who had been hospitalized with influenza. They found that compared to those who'd been hospitalized with the seasonal flu, COVID-19 survivors who'd been hospitalized saw increased risk and magnitude of post-infection lung problems and other disorders.
The findings do not suggest that everyone who gets COVID-19 will have long-term health effects.
"The majority of people will have no problems and no consequences down the road. They'll get maybe sick for a day or two or three or four. They'll get over the hump. They'll regain their energy, cough will go away, shortness of breath will go away, fever will go away, and they will feel fine," he says.
"But it is true, though, that a minority of people, even if they have mild disease, they are at higher risk of developing some of the consequences that we described here. So the risk is not zero – it's small, but it's not trivial."
The study's subjects skewed male, given the veterans who use VA health care. But while the VA population is about 88% male, the study's large size means that it still included more than 8,800 women who contracted COVID-19.
The U.S. has had at least 31 million confirmed cases of the coronavirus. It's not clear exactly what portion of patients experience its lingering symptoms, but Al-Aly says it's estimated to be 8-10%.
The takeaway from this study, Al-Aly says, is that the health care system needs to get ready for a lot of people living with the consequences of long COVID-19.
"That really represents a significant burden on the health care system that we need to be prepared for," he says. "We shouldn't really act surprised two or three years down the road, when people are having of a lot more diabetes or a lot more people with heart disease show up. We shouldn't really act surprised. We should prepare for it now."
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