A new study has found that although there appears to be no association between microscopic colitis (MC) and a higher risk for severe coronavirus disease 2019 (COVID-19), the collagenous colitis (CC) subtype in MC may be associated with an increased risk for severe COVID-19 compared with the lymphocytic colitis (LC) subtype. Findings from this study were published in Gastroenterology.
The study included patients from a Swedish nationwide pathology cohort who were diagnosed with MC between 1990 and 2016. Each patient with MC was alive and living in Sweden as of February 2020. The study investigators matched each patient with ≤5 population comparators.
The primary outcomes of the study were hospital admission with confirmed COVID-19 and the incidence of severe COVID-19. The severe COVID-19 outcome was a composite outcome comprising COVID-19 intensive care admission, death because of COVID-19, or death within 30 days of COVID-19 hospital admission.
Overall, there were 10,552 propensity-score matched patients with an MC diagnosis between 1990 and 2017, and these patients were matched to a total of 52,624 population comparators. In this study, there were 359 patients with CC subtype (mean age, 65.1 years; 85.2% women) and 172 patients with LC subtype (mean age, 64.7 years; 78.5% women) who had genotypes available for analysis.
The primary analysis found no association between MC and the risk for hospitalization for COVID-19 (hazard ratio [HR] 1.25 [95% CI, 0.93-1.69]) or severe COVID-19 (HR 1.39 [95% CI, 0.94-2.03]) compared with matched population comparators.
In patients with the CC subtype, the investigators found a significantly increased risk for COVID-19 hospital admission (HR 3.4 [95% CI, 2.03-5.7]) and severe COVID-19 (HR 2.48 [95% CI, 1.33-4.63]). In contrast, there was no association between LC and risk for COVID-19 hospitalization (HR 0.81 [95% CI, 0.55-1.2]) or severe COVID-19 (HR 1.03 [95% CI, 0.62-1.69]).
There was an increased risk for COVID-19 in patients with MC (HR 1.27 [95% CI, 1.08-1.49]) and CC (HR 1.72 [1.29-2.28]), but no association was found for LC (HR 1.11 [95% CI, 0.91-1.36]). Adjustments for the use of oral steroids and proton pump inhibitors found a similar association between the CC subtype and COVID-19–related hospital admission (HR 3.2 [95% CI, 1.46-6.99]) and severe COVID-19 (HR 2.19 [95% CI, 0.92-5.12]).
The rs13071258 A variant, which the investigators explained represents 3p21.31 risk locus for severe COVID-19, was more common in patients with the CC subtype compared with patients with the LC subtype (allele frequencies, 0.097 and 0.047, respectively; P =.00464).
Limitations of this study included the lack of individual-level data on medications, lifestyle factors, and comorbidities at the time of COVID-19 diagnosis.
The researchers concluded that if additional studies corroborate their findings, these studies “may suggest the existence of specific pathogenetic mechanisms shared between COVID-19 infection and or severity and CC.”
Khalili H, Zheng T, Söderling J, et al. Association between collagenous and lymphocytic colitis and risk of severe COVID-19. Published online February 18, 2021. Gastroenterology. doi:10.1053/j.gastro.2021.02.029