Severe infections in Portuguese patients with rheumatoid arthritis under biologic treatment - a multicenter, nationwide study (SIPPRA-B Study).

Introduction: Despite years of experience with biological disease modifying anti-rheumatic drugs (bDMARD) in rheumatoid arthritis (RA), little is known about differences in infectious risk among bDMARDs. The aim of this study was to assess the incidence and type of infections in RA patients on bDMARDs and to determine possible predictors.

Methods: A retrospective multicenter cohort study that included patients registered in the Rheumatic Diseases Portuguese Registry (Reuma.pt) with RA, and exposed to at least one bDMARD until April 2021. RA patients under bDMARD and with at least one episode of severe infection (SI), defined as infection that requires hospitalization, use of parenteral antibiotics or that resulted in death, were compared to patients with no report of SI. Demographic and clinical data at baseline and at the time of each SI were collected to establish comparisons between different groups of bDMARDs. Comparisons between different bDMARDs were assessed and logistic regression was performed to identify predictors of SI.

Results: We included 3394 patients, 2833 (83.5%) female, with a mean age at RA diagnosis of 45.5±13.7 years. SI was diagnosed in 142 of the 3394 patients evaluated (4.2%), totaling 151 episodes of SI. At baseline, patients with SI had a significantly higher proportion of prior orthopedic surgery, asthma, interstitial lung disease, chronic kidney disease and corticosteroid use, higher mean age and longer median disease duration at first bDMARD. Nine patients died (6.0%). Ninety-two SI (60.9%) occurred with the first bDMARD, the majority leading to discontinuation of the bDMARD within 6 months (n=75, 49.7%), while 65 (43.0%) restarted the same bDMARD and 11 (7.3%) switched to another bDMARD (6 of them to a different mechanism of action). In the multivariate analysis, we found that chronic kidney disease, asthma, infliximab, corticosteroid use, interstitial lung disease, previous orthopedic surgery, higher Health Assessment Questionnaire and DAS284V-ESR are independent predictors of SI.

Conclusion: This study described the incidence and types of SI among Portuguese RA patients on biologics, identifying several predictors of SI, both globally and with different bDMARDs. Physicians should be aware of the real-word infectious risk in RA patients on bDMARDs when making treatment decisions.