Patient-related factors influencing the effectiveness and safety of Janus Kinase inhibitors in rheumatoid arthritis: a real-world study

In real-world scenarios, Janus Kinase (JAK) inhibitors are often offered to "difficult-to-treat" rheumatoid arthritis patients, quite different from those included in randomized controlled trials. Our study aimed to evaluate the influence of patient-related factors on the effectiveness and safety of JAK inhibitors in real-world clinical practice. This observational retrospective study involved rheumatoid arthritis patients who received treatment with either tofacitinib, baricitinib, upadacitinib, or filgotinib. At 12 months of treatment, reasons for and rates of JAK inhibitor treatment discontinuation were examined. Treatment retentions were analyzed through Cox proportional hazard regression models and Kaplan-Meier estimates. Patient-related factors that could influence treatment retention were evaluated for the discontinuation reasons of lack of effectiveness and adverse events. At 12 months of treatment, discontinuation rates for 189 JAK inhibitor treatments were: lack of effectiveness (24.3%), adverse events (20.6%), and other reasons (3.7%). The remaining 51.4% represents the treatment continuation rate. No patient-related factors evaluated had an influence on treatment discontinuation due to lack of effectiveness. Ae significantly increased the risk of treatment discontinuation due to adverse events (p = 0.030). In terms of age, at 12 month of treatment, discontinuation rates due to adverse events were: < 65 years, 14.4% vs. 65 years or older, 26.3% (p = 0.019). Rheumatoid arthritis patients aged 65 years or older showed an increased risk of JAK inhibitor treatment discontinuation due to adverse events. Factors not related to treatment discontinuation were: sex, rheumatoid arthritis disease duration, rheumatoid arthritis disease activity, seropositivity for rheumatoid factor, seropositivity for anti-cyclic citrullinated peptides, number of prior biologic treatments, number of prior JAK inhibitor treatments, concomitant use of glucocorticoids, and concomitant use of conventional synthetic disease-modifying antirheumatic drugs.