More than 1 in 5 COVID survivors may develop long COVID, CDC study suggests

According to a study published this week by the Centers for Disease Control and Prevention, more than one in five adults in the US who have recovered from COVID-19 may end up developing a long-term condition.

The post-COVID conditions include heart, lung, kidneys, cardiovascular, gastrointestinal, neurological, and mental health conditions. The risk of developing respiratory and lung conditions, including pulmonary embolisms, was more than double for COVID survivors. Respiratory conditions and pain were the most common post-COVID conditions.

Older survivors were more likely to develop cardiac dysrhythmia than younger ones. The risks for survivors 65 and up were greater than for younger people.

Post-COVID conditions affecting the nervous system can lead to early entry into supportive services or investment of additional resources into care in the older age group. Post-COVID conditions can affect a patient's ability to contribute to the workforce and may have economic consequences for survivors and their dependents.

More than 83 million cases of COVID-19 have been reported in the US, and the findings mean that millions could develop long-term symptoms, requiring additional care and resources.

Study design

The authors mined electronic health records from a national database containing information on 63.4 million adult patients from all 50 states. 353,164 patients were diagnosed with COVID-19 between March 2020 and November 2021. The COVID-19 patients were matched in a ratio of one to five with the control patients who had visited a health care facility during the same month. For at least a month and a year, all of the survivors and controls were monitored.

Patients with a history of any of the 26 conditions linked to COVID-19 were excluded from the study.

The percentage of COVID-19 survivors who developed a post-COVID condition was higher than the percentage of controls. In the 18 to 64 age group, more survivors developed a post-COVID condition than controls. In the 65 and up group, more than half of survivors developed a post-COVID condition, compared with less than a quarter of controls.

The absolute risk difference between the percentage of COVID survivors and controls who developed a post-COVID condition was 20.8 percentage points for those between 18 and 64, and 26.9 percentage points for those 65 and up. The CDC estimates that one in five adults from 18 to 64 and one in four from 65 and up develop at least one post-COVID condition.

The study only taps into electronic health records from one software source, so it's possible that the results are not generalizable to the entire US. Some demographic details, such as geographic location, were not accounted for. Because it is based on electronic health records, it may be biased towards those who are more likely to seek care.

The authors note that their findings are in line with the findings of several large studies that indicated that post-COVID incident conditions occur in 20% of patients. They conclude that the findings can increase awareness for post-COVID conditions and improve post-acute care and management of patients after illness.