Serious Infections were Rare Among Patients with PsA, axSpA

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Of the 333 patients with PsA and 457 patients with axSpA, there were 1.09 serious infections per 100 patient years (95% CI .85 – 1.35).

Although nonserious infections were common, serious infections were rare in both randomized controlled trials (RCTs) and real-life studies of patients with psoriatic arthritis (PsA) or axial spondyloarthritis (axSpA), according to a study published in Rheumatic and Musculoskeletal Diseases.1

“Most of the data on the risk of infection in patients treated with biologic/targeted synthetics disease-modifying antirheumatic drugs (b/tsDMARDs) are known from their use in other inflammatory diseases such as rheumatoid arthritis or psoriasis,” wrote co-lead investigator Fabienne Coury, MD, PhD, associated with the department of rheumatology, Lyon-Sud Hospital Hospices civiles de Lyon, France, and colleagues. “However, characteristics of patients differ from 1 inflammatory disease to another, particularly in terms of age, comorbidities, pathophysiology of rheumatic diseases and associated treatments. Thus, it is difficult to extrapolate safety data from different populations.”

Infections are a common side effect of these molecules, categorized as either serious or nonserious. Nonserious infections include influenza, urinary tract infections, upper respiratory tract infections, gastrointestinal infections, candida infections, herpes infections, nasopharyngitis, and skin infections. While nonserious infections are not life-threatening, they may play a role in poor treatment compliance.2

To determine the incidence of infection, investigators included a large group of patients with spondyloarthritis (SpA) treated with tumor necrosis factor inhibitors (TNF), Janus kinase inhibitors (JAKs), interleukin (IL)-17 inhibitors, IL-23 or IL-12/23 inhibitors, phosphodiesterase 4 inhibitors, or cytotoxic T-lymphocyte associated protein 4-Ig. A meta-analysis of RCTs, observational studies, and open-label extension studies was performed. Data from PubMed and the Cochrane Central Register of Controlled Trial (CENTRAL) were included. Serious infections were those categorized as life-threatening, required intravenous antibiotics, or those that required hospitalization. Incidence rates were evaluated by treatment class and study type to create a 95% confidence interval (CI).

Of the 333 patients with PsA and 457 patients with axSpA, there were 1.09 serious infections per 100 patient years (95% CI .85 – 1.35). Similar incidence rates were observed in both PsA and axSpA cohorts (.96 per 100 patient years 95% CI .69 – 1.28; 1.09 per 100 patient years 95% CI .76 – 1.46, respectively).

Compared with the observational studies included, the incidence rate was lower in the RCTs (.77 per 100 patient years 95% CI .41 – 1.20 vs 1.68 per 100 patient years 95% CI 1.03 – 2.47, respectively). Additionally, in patients with PsA, the lowest incidence rate was reported in patients receiving IL-12/23 inhibitors (.29 per 100 patient years 95% CI .00 – 1.03).

A total of 53 nonserious infections per 100 patient years were reported in 7257 patients in the PsA cohort and 5638 patients in the axSpA cohort. The incident rate was higher in the RCTs when compared with observational studies (69.95 per 100 patient years 95% CI 61.59 – 78.84 vs 15.37 per 100 patient years 95% CI 5.11 – 30.97, respectively).

Investigators noted a limitation was the heterogeneity in the observational studies. The subgroup analyses did not improve the heterogeneity and the meta-regression analyses for the year of publication, the duration of follow-up, and the number of concomitant medications were not significant in the univariate analysis. This may in turn have explained the funnel plot asymmetry. Additionally, publication bias could not be excluded.

“Nonserious infections were frequent in RCTs although their impact is currently poorly studied in the literature,” investigators concluded. “The impact of the frequent finding of NSI in patients treated with b/tsDMARD, mainly in RCTs studies, needs to be explored.”


  1. Aureal M, Seauve M, Laplane S, Lega JC, Cabrera N, Coury F. Incidence of infections in patients with psoriatic arthritis and axial spondyloarthritis treated with biological or targeted disease-modifying agents: a systematic review and meta-analysis of randomised controlled trials, open-label studies and observational studies. RMD Open. 2023;9(3):e003064. doi:10.1136/rmdopen-2023-003064
  2. Pan SMD, Dehler S, Ciurea A, et al. Comparison of drug retention rates and causes of drug discontinuation between anti-tumor necrosis factor agents in rheumatoid arthritis. Arthritis Rheum 2009;61:560–8. doi:10.1002/art.24463 Available: