More than three-quarters of Americans long diagnosed with Covid were not ill enough to be hospitalized for their initial infection, a new analysis of tens of thousands of home insurance claims reported Wednesday.
The researchers analyzed data from the first few months after doctors began using a special diagnosis code for the condition that had emerged over the past year. The results paint a sobering picture of the severe and ongoing impact of Covid on people’s health and the American healthcare system.
Long Covid, a complex constellation of ongoing or new post-infection symptoms that can last months or longer, has become one of the most frightening legacies of the pandemic. Estimates of how many people might ultimately be affected range from 10 to 30 percent of infected adults; A recent report from the US Government Accountability Office says that between 7.7 million and 23 million people in the United States may have long-term illness from Covid. But much remains unclear about the prevalence, causes, treatment and consequences of the disease.
The new study adds to a growing body of evidence that while hospitalized patients are at higher risk of long-term Covid, people with mild or moderate initial coronavirus infections – who make up the vast majority of coronavirus patients – however, may still experience debilitating post-Covid symptoms such as breathing problems, extreme fatigue, and cognitive and memory problems.
“It’s creating a pandemic of people who weren’t hospitalized but ended up with this increased disability,” said Dr. Paddy Ssentongo, an assistant professor of infectious disease epidemiology at Penn State, who was not involved in the new study.
The analysis, based on what is reported to be the largest database of private health insurance claims in the United States, found 78,252 patients diagnosed with the new International Classification of Diseases code – diagnostic code U09.9 for “Post COVID-19 condition, unspecified.” – between October 1, 2021 and January 31, 2022.
dr Claire Steves, a clinical academic and doctor at King’s College London who was not involved in the new research, said the total number of people who received the diagnosis was “huge” because the study only covered the first four months after the diagnosis code was introduced and did not include people covered by government health programs such as Medicaid or Medicare (although it did include people on private Medicare Advantage plans). “That’s probably a drop in the ocean compared to the actual number,” said Dr. Steve’s.
The study, conducted by FAIR Health, a nonprofit organization that focuses on healthcare costs and insurance issues, found that 76 percent of long Covid patients did not require hospitalization because of their initial coronavirus infection.
Another striking finding was that while two-thirds of the patients had pre-existing health problems on their medical records, nearly a third did not, a much larger percentage than Dr. Ssentongo expected. “These are people who have been sane and are like, ‘Guys, there’s something wrong with me,'” he said.
The researchers plan to continue to follow patients to see how long their symptoms last, but Robin Gelburd, FAIR Health’s president, said the organization decided to release data from the first four months now, “given the urgency” of the problem.
She said the researchers were working to answer some of the questions not addressed in the report, including providing details on some patients’ past health conditions to determine whether certain medical conditions put them at higher risk of long Covid.
The organization also plans to analyze how many patients in the study were vaccinated and when, Ms Gelburd said. More than three quarters of the patients in the study were infected in 2021, most of them in the last half of the year. On average, patients continued to suffer from long-term Covid symptoms qualifying for the diagnosis four and a half months after their infection.
The results point to a potentially amazing impact of Long Covid on people in the prime of life and on society at large. Almost 35 percent of the patients were between 36 and 50 years old, while almost a third were 51 to 64 years old and 17 percent were 23 to 35 years old. Children have also been diagnosed with post-Covid illness: nearly 4 percent of patients were aged 12 or younger, while nearly 7 percent were between the ages of 13 and 22.
Six percent of the patients were 65 years and older, a proportion that most likely reflects the fact that patients covered by the regular Medicare program were not included in the study. They were much more likely than the younger long-Covid groups to have pre-existing chronic conditions.
The analyzed insurance data contained no information about the race or ethnicity of the patients, the researchers said.
The analysis, which Ms Gelburd said was peer-reviewed by an independent academic evaluator, but not officially peer-reviewed, also calculated a patient risk score, a way of estimating how likely people are to use health resources. Comparing all of the insurance claims patients had up to 90 days before contracting Covid with their claims 30 days or more after becoming infected, the study found that the average risk scores for patients increased in each age group.
Ms Gelburd and other experts said the results suggested the impact of long-Covid was not just limited to increased medical expenses. They signal “how many people are leaving their jobs, how many are being granted disability status, how many are absent from school,” Ms Gelburd said. “It’s like a pebble being thrown into the lake, and these waves orbiting that pebble are concentric circles of impact.”
Because the study only covers a privately insured population, Dr. Ssentongo, she is almost certainly underestimating the scope and burden of the long Covid, especially as low-income communities have been disproportionately affected by the virus and often have less access to health care. “I think it could get even worse if we added the Medicaid population and all these other people that would have been missed in the study’s data,” he said.
Sixty percent of patients with the post-Covid diagnosis were female, the study reported, compared to 54 percent of all Covid patients in the FAIR Health database. In the oldest and youngest age groups, however, there were roughly equal numbers of men and women.
“I think there’s a preponderance in women for this condition,” said Dr. Steves, adding that the reasons could include differences in biological factors that make women more susceptible to autoimmune diseases.
The insurance claims showed nearly a quarter of the post-Covid patients had difficulty breathing, nearly a fifth had a cough, and 17 percent had been diagnosed with malaise and fatigue, a broad category that could include problems like brain fog and exhaustion that manifest after physical or mental illness mental activity worse. Other common problems included abnormal heartbeats and trouble sleeping.
Generalized anxiety disorder was more common among 23- to 35-year-olds than other age groups, the study reported, while hypertension was more common among the oldest patients.
Last year, FAIR Health published a study tracking the insurance records of almost two million people who had contracted Covid. It found that nearly a quarter of them – 23 percent – sought medical treatment for new illnesses a month or more after they were infected.
The new study sought to determine how common certain symptoms were before patients were infected compared to the period during which the same patients were diagnosed with post-Covid illness. It turned out that some typically unusual health problems were much more likely to emerge during a long Covid time. For example, muscle problems were 11 times more likely in patients with long Covid, pulmonary embolism was 2.6 times more likely and certain types of brain-related disorders were twice as likely, the study found.
Like previous studies, the report found that patients who required hospitalization for their initial infection were at greater risk of long-term symptoms than patients who were not hospitalized. The report came to that conclusion because about 24 percent of patients diagnosed with post-Covid illness had been hospitalized — more of them male than female — while only about 8 percent of all coronavirus patients required hospitalization .
With the vast majority of people not requiring hospitalization for their infection, medical experts said this and other studies suggest many people with mild or moderate initial illness will end up with lingering symptoms or new health problems post-Covid.
Ms Gelburd and medical experts said that as doctors become familiar with the U09.9 code, they may use it in different circumstances than they did in the first four months. A recent analysis revealed that doctors’ use of the code has been patchy.
Given the likely extent of long Covid, Dr. Ssentongo that in the future doctors will ask patients if they have ever been diagnosed with post-Covid illnesses, just as doctors ask about other previous medical problems so that they can treat patients appropriately.
“Post-Covid syndrome may become one of the most common pre-existing comorbidities in the future,” he said.