Tuberculosis Risk in Ankylosing Spondylitis, Other Spondyloarthritis, and Psoriatic Arthritis in Sweden: A Population‐Based Cohort Study

Abstract

Objective Rheumatoid arthritis is a risk factor for tuberculosis ( TB ), particularly following treatment with biologic agents. Since these therapies are increasingly used in ankylosing spondylitis ( AS ), other types of spondyloarthritis (SpA), and psoriatic arthritis (PsA), we investigated the corresponding TB risks in these patients. Methods We identified individuals with AS /SpA/PsA, and non‐ AS /SpA/PsA comparators by linking Swedish national patient, population, TB , and rheumatology registers, and followed them for TB occurrence. Incidence rates were estimated for biologic‐naive and biologic‐exposed patients and the comparators. We calculated hazard ratios ( HR s), adjusted for age, sex, and country of birth. Results Included in this study were 38,702 patients with AS /SpA/PsA, and 200,417 persons from the general population. Among the patients, 11 active TB cases were identified, with an incidence rate (per 10 5 ) of 22 (95% confidence interval [95% CI ] 8.3–59.2) for biologic‐exposed patients, 2.7 (95% CI 1.3–5.6) for biologic‐naive patients, and 2.4 (95% CI 1.8–3.3) for non‐ AS /SpA/PsA comparators. The adjusted HR comparing biologic‐naive patients to the general population was 1.2 (95% CI 0.5–2.7), and 7.5 (95% CI 1.9–29) comparing biologic‐exposed to biologic‐naive patients. Conclusion Biologic‐naive AS /SpA/PsA patients are not at an increased TB risk in Sweden. Following treatment with biologic agents, the risk increased, but the absolute TB risk was low.