COVID-19 may increase the risk of autoimmune inflammatory rheumatic diseases (AIRDs) for up to 1 year after infection, according to a two-country study published today in the Annals of Internal Medicine.
The study, led by researchers from the Broad Institute at MIT and Harvard and from Kyung Hee University in Seoul, South Korea, analyzed national claims databases from more than 10 million Korean and 12 million Japanese patients aged 20 years and older diagnosed as having COVID-19 from January 2020 to December 2021.
The study period was dominated by the wild-type virus and then the Delta variant. The COVID-19 patients were compared with matched flu patients from the same period and uninfected controls.
Of the Korean participants, 3.9% had a history of COVID-19, and 0.98% had a history of flu. Among the Japanese participants, 8.2% had COVID-19, and 0.99% had flu.
Vaccination appears protective
After propensity-score matching, COVID-19 patients were at a 25% to 30% increased risk for new-onset AIRD after the first 30 days post-infection, compared with uninfected controls (adjusted hazard ratio [aHR], 1.25) and flu patients (aHR, 1.30).
After adjustment, the risks for all-cause AIRD, connective tissue disease, untreated AIRD, and treated AIRD were significantly higher after COVID-19 infection than those in uninfected or flu patients in both the Korean and Japanese cohorts. The risk of new-onset, all-cause AIRD appeared to decline with time and fell off after 1 year.
Care strategies for patients who survive COVID-19 should pay close attention to manifestations of AIRD, particularly after severe COVID-19.
Greater severity of COVID-19 infection was tied to an increased risk of new-onset, untreated, and treated AIRD. The wild-type virus and the Delta variant were both associated with increased risk of AIRD.
Relative to unvaccinated COVID-19 patients, the rate of AIRD was lower among COVID-19 patients who had received one vaccine dose (HR, 0.59) or two or more doses (HR, 0.42), regardless of whether the vaccine was the mRNA or viral-vector type. While receipt of at least one dose was linked to a reduced risk of AIRD in patients with mild COVID-19, this was not the case for those with moderate or severe disease.
The findings held true in subgroup analyses by sex, age-group, annual income, history of infectious respiratory disease, Charlson Comorbidity Index score, body mass index, smoking status, alcohol consumption, and level of aerobic exercise.
"This population-based cohort study shows that the increased risk for incident AIRD extends up to 12 months after SARS-CoV-2 infection," the study authors wrote. "Care strategies for patients who survive COVID-19 should pay close attention to manifestations of AIRD, particularly after severe COVID-19."
