New study categorizes long COVID symptoms, allowing for earlier detection

A recent study published in the science journal “Nature Medicine” found that symptoms of long COVID-19 can be categorized into four subtypes, a new finding that can allow for earlier detection of the condition.

The study analyzed nearly 35,000 patients from New York and Florida and distilled over 137 symptoms into four main categories. Researchers used machine learning to analyze the electronic health data of patients with lingering symptoms 30-180 days after a documented infection.

“When you’re over your COVID illness a lot of people don’t have any consequences,” said Dr. Jason Block, an internist at Brigham and Women’s Hospital who co-wrote the study. “But not everyone returns to their baseline state.” He explained that symptoms of long COVID may not be permanent, but people should be aware of long-term COVID consequences so “they don’t have to suffer in silence.”

The study’s machine learning algorithm analyzed “a vast amount of data,” of disparate symptoms, he said, and grouped them into the four ways they most commonly occur in tandem. 

1. 34% of patients showed symptoms affecting cardiac and renal (kidney) systems 
2. 33% of patients showed symptoms affecting respiratory systems, sleep, and anxiety
3. 23% of patients showed symptoms affecting the musculoskeletal and nervous systems
4. 10% of patients showed symptoms affecting the digestive and respiratory systems.

Most patients fell into the first two subtypes, with symptoms of chest pain, heart palpitations, cough, and difficulty sleeping. And while these common ailments can be easily found in past research or on the CDC’s website, clustering long COVID symptoms into categories is a recent development, seen in only a few other studies.

Long COVID symptoms have been studied extensively, but previous literature “typically focused on a couple of conditions rather than focusing on the clusters of conditions together,” Block said. 

According to the Centers for Disease Control, nearly one in five U.S. adults who had COVID — and 7.5% of all adults in the U.S. — have long COVID. For both clinicians diagnosing patients and those suffering from symptoms themselves, the study’s findings allow many to take necessary medical action earlier, rather than later.

“Awareness allows you to make the connection,” Block said. “Being mindful of that, and more aware in that period of time, means patients can get in contact with their doctors and manage symptoms sooner.”