Background: This research describes the incidence and factors associated with opportunistic infections in rheumatoid arthritis (RA) patients treated with biological disease-modifying antirheumatic drugs (bDMARDs).
Methods: A retrospective longitudinal study was carried out from 2007 to 2018. We included RA patients treated with a tumor necrosis factor (TNF)-targeted bDMARD or non-TNFtargeted bDMARD from the start of bDMARDs. An independent variable was the development of an indicator of opportunistic infection after biological (IOIb) treatment. Secondary variables included sociodemographic, clinical, and treatments. We used survival techniques to estimate the incidence of IOIb, per 1000 patient-years (95% CI). We performed a Cox multivariate regression analysis model to compare the risk of IOIb. Results were expressed as a hazard ratio (HR).
Results: A total of 441 RA patients were included, that started 761 different courses of bDMARDs. A total of 81% were women with a mean age at first bDMARD of 57.3 ± 14 years. A total of 71.3% of the courses were TNF-targeted bDMARDs and 28.7% were non-TNF-targeted bDMARDs. There were 37 IOIb (25 viral, 6 fungal, 5 bacterial, 1 parasitic). Nine of these required hospitalization and one died. The global incidence of IOIb was 23.2 (16.8–32). TNFtargeted bDMARDs had 25 IOIb, incidence 20.5 (13.9–30.4), and non-TNF-targeted bDMARDs had 12 IOIb, incidence 31.7 (18–55.9). In the multivariate analysis, glucocorticosteroids (HR 2.17, p = 0.004) and lower lymphocyte count increased the risk for IOIb (HR 0.99, p = 0.005).
Conclusions: The incidence of IOIb due to bDMARDs was 23 cases per 1000 patientyears. Close monitoring should be taken in the RA patients treated with bDMARDs and glucocorticosteroids, mainly in elderly patients and those with a low total lymphocyte count at the beginning of bDMARD treatment.