Although severe COVID-19 has been linked to rheumatoid arthritis (RA), the role of RA phenotypes in this connection has been understudied. This study’s primary objective was to examine the correlations between RA and interstitial lung disease phenotypes, serostatus, and bone erosions of COVID-19 severity. Researchers conducted a retrospective, comparative, multicentre cohort study at the Mayo Clinic and the Massachusetts General Hospital, and the Brigham and Women’s Hospital in the United States. Patients with rheumatoid arthritis who had COVID-19 between March 1, 2020, and June 6, 2021, and who met 2010 American College of Rheumatology/European League Against Rheumatism classification criteria were matched 1:5 with patients without rheumatoid arthritis based on age, sex, and calendar date (comparators). Electronic health records from the Mayo Clinic and the Massachusetts General Hospital in Boston provided the data. They looked at subsets of RA patients based on phenotypic criteria such as the presence of rheumatoid arthritis-associated interstitial lung disease, seropositivity (for anti-cyclic citrullinated peptide, rheumatoid factor, or both), and the presence of bone erosions. Hospitalization or death from COVID-19 qualified as severe. They compared RA and its subsets to a control group and used Cox regression to estimate hazard ratios (HR) for severe COVID-19. During the study period, investigators found 582 RA patients and 2875 healthy controls who tested positive for COVID-19. About 421 (72%) of 582 were female, and 161 (28%) were male; the mean age was 62 [SD 14] years; 457 (79%) were White, 65 (11%) were Hispanic or Latino, and 41 (7%) were Black. Interstitial lung disease affected 50 (9%) of 582 RA patients, seropositivity was found in 388 (68%) of 568, and 159 (27%) of RA patients experienced bone erosions. Out of 582 RA patients, 126 (22%), experienced severe COVID-19, compared to 363 (13%), in the control group. Patients with rheumatoid arthritis were at increased risk for severe COVID-19, with a hazard ratio (HR) of 1.75 (95% CI 1.45-2.11). Interstitial lung illness caused by rheumatoid arthritis increased the risk of severe COVID-19 by a factor of 2.50 (1.66-3.77), compared to the control group. Patients with rheumatoid arthritis who tested positive for antibodies to COVID-19 (hazard ratio [HR] 1.97 [95% CI 1.58-2.46]) or who had the erosive disease (1.93 [1.41-2.63]) had a greater probability of developing severe COVID-19. Patients with rheumatoid arthritis, regardless of phenotypic subtype, were at higher risk for severe COVID-19, and this was especially true for those with interstitial lung disease. These results raised the possibility that the presence of interstitial lung disease in individuals with rheumatoid arthritis, or the therapy for it, was a major factor in the development of catastrophic COVID-19 outcomes.