Researchers analyzed data from a large insurance company in the United States. They found an increased risk of other medical conditions after recovering from COVID-19 irrespective of pre-existing conditions or age.
COVID-19 caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a range of manifestations, from no symptoms to severe illness. Although complete recovery may occur within a few days in mild to moderate illness, the longer-term effects of the disease in humans are as yet unknown.
Studies have reported that many recovered patients experience different symptoms well after complete recovery, affecting their physical, mental, and social health. Evidence from survivors of other coronavirus infections like MERS and SARS suggests long-term effects are not uncommon.
There have only been a few studies that have looked at the effects of the disease in the long term, mainly in patients with severe disease who were hospitalized. But, these studies may not be representative of the general population.
Researchers investigated the excess risk and relative hazards for developing long-term effects of COVID-19 and reported their results in a paper published in the BMJ.
Analyzing excess risk
The team used data from a large health plan in the United States, with information on lab results and hospital admissions. The study participants included adults between 18 and 65 years of age who tested positive for the virus. They compared the data for these participants with data for participants before the pandemic. They followed the participants for six months after the disease to check for any new clinical diagnoses.
About 3% of the total study participants were identified as being positive for SARS-CoV-2 infection. These people were more likely to be younger women of a lower socioeconomic status living in predominantly Hispanic or black neighborhoods compared to comparable individuals before the pandemic who had lower respiratory tract illness.
The team found that about 86% of the people had no new clinical manifestations that required medical care during the follow-up. About 14% had one new clinical issue, which was about 5% more than the pre-pandemic control group, and about 4% had more than one type of clinical issue. People infected with SARS-CoV-2 had a higher proportion of clinical issues compared to the control group.
Analysis of the data showed a low excess risk for other clinical issues because of SARS-CoV-2 infection. However, the hazard ratios for infected persons were large, up to about 25, highest during the first month after infection. They were still high for some conditions like hypertension, diabetes, and fatigue up to six months after infection.
The excess risk increased with age, with people above 50 years having the most significant risk. The excess risk was similar for men and women except for a few conditions like fatigue, loss of smell, kidney injury, and a few others.
Increased risk during four months after illness
The results suggest that COVID-19 is not unique in causing other medical issues after recovery. Although the risk increased with age, pre-existing conditions, and severe illness, even others without these conditions were also at risk for new medical issues coming up after recovery. There was an increased and persistent risk for about four months after the illness.
The risk of certain medical conditions like cardiac irregularities, deep vein thrombosis, anxiety, liver abnormalities, and fatigue was higher among COVID-19 survivors. Studies have shown that patients who recovered from SARS and MERS have arrhythmia and tachycardia and conditions of the central and peripheral nervous system.
Although the study was able to quantify the risk for healthy, younger adults, the authors were not able to identify race or ethnicity at the individual level. Further, since the study participants had to be continuously insured, uninsured people were omitted. Other limitations were not including death as an outcome in the study and the possibility of misclassification of individuals.
For doctors to manage and treat patients, it is vital to understand the occurrence and history of clinical conditions because of COVID-19. “Our results provide clinicians with a comprehensive understanding of the excess risk for over 50 clinical morbidities across multiple organ systems affecting adults aged ≤65 after the acute phase of SARS-Cov-2 infection,” write the authors. Knowing the risk magnitude can help manage these issues better.