Biologics reduced infections in ankylosing spondylitis and psoriatic arthritis under immunosuppressants.

Abstract

Background: Biologic disease-modifying antirheumatic drugs (bDMARDs) alleviate inflammation but may have immunocompromising effects. Previous studies evaluating infection risks in spondyloarthritis (SpA) have yielded inconsistent conclusions. We investigated infection risk in patients with ankylosing spondylitis (AS) and psoriatic arthritis (PsA) receiving bDMARDs compared with that of those receiving only conventional synthetic disease-modifying antirheumatic drugs.

Methods: Using the database at Taipei Veterans General Hospital (from January 1, 2011, to September 30, 2018), we retrospectively identified eligible SpA patients and applied a two-step verification process to confirm serious infections requiring hospitalization. Time-to-event outcomes were analyzed using multivariable Cox regression adjusted for age, sex, comorbidities, and concomitant medications. Site-specific analyses characterized infection patterns.

Results: We included 5568 patients with SpA (4,784 AS, 784 PsA), with a mean age of 42.1 years and male predominance (68.4%). bDMARD prescription was associated with a reduced risk of first serious infection in the overall SpA cohort (adjusted hazard ratio [aHR] = 0.247, p = 2.4782 × 10 -7 ), as well as in AS (aHR = 0.253, p = 4.73 × 10 -4 ) and PsA (aHR = 0.207, p = 6.69 × 10 -4 ). bDMARD prescription was also associated with significantly lower risks of skin and soft tissue infection in PsA (aHR = 0.252, p = 1.1905 × 10 -2 ) and pneumonia/gastrointestinal infections in SpA. Sulfasalazine (SSZ) was independently associated with an increased infection risk (aHR = 1.630, p = 2 .6276 × 10 Sulfasalazine 2 ); nonsteroidal anti-inflammatory drugs were associated with a reduced risk in AS.

Conclusion: Adjunctive bDMARD therapy was associated with a substantially reduced risk of serious infection in AS, PsA, and the overall SpA cohort, potentially because of effective systemic inflammation suppression in SpA and restoration of the skin barrier in PsA. The elevated risk associated with SSZ in AS may reflect channeling bias in refractory patients. Early and appropriate use of bDMARDs in SpA may achieve disease control without compromising immune defense against infections.