Performance of Janus kinase inhibitors in psoriatic arthritis with axial involvement in indirect comparison with ankylosing spondylitis: a retrospective analysis from pooled data.

BACKGROUND AND OBJECTIVE: As the well-acknowledged autoimmune disease, Janus kinase (JAK) is thought to play important roles in the progression of tissue injury in spondyloarthropathy. From a current perspective, JAK inhibitors could be applied to both psoriatic arthritis (PsA) and ankylosing spondylitis (AS). Nonetheless, it is reasonable to doubt whether PsA and AS differentially respond to JAK inhibitors. METHODS: Different databases were searched for full-text publication based on inclusion and exclusion criteria. For data-pooling, a fixed-effect model was applied if heterogeneity was not detected. All results of the analysis were illustrated as forest plots. Publication bias was assessed using Begg's adjusted rank correlation test. The standard mean difference (SMD) was calculated in continuous variables. The pooled odds ratio was calculated in categorical variables. RESULTS: Nine clinical studies were finally included with a 3-month follow-up. The efficacy and safety of JAK inhibitors were comprehensively investigated. JAK inhibitors were proved to be effectively improving disease condition within 3 months (12 weeks) in both PsA and AS. Besides, psoriasis-related dermal lesions could also be improved by JAK inhibitors. Dose-dependent effects suggested that higher dose tofacitinib could bring not only a higher level of treatment response but also more safety concerns. CONCLUSION: JAK inhibitors were proved to be effective in improving arthritis symptoms and enhancing the quality of life in both PsA and AS patients. Compared with AS, JAK inhibitors seemed to perform better in PsA treatment. However, the frequency of adverse events PsA and AS in comparison with the placebo group showed no difference. Higher dose of tofacitinib could attain better treatment response without increasing adverse events in short-term follow-up. KEY POINTS: • JAK inhibitors were proved to be effective in improving arthritis symptoms and enhancing the quality of life in both PsA and AS patients. • Compared with AS, JAK inhibitors seemed to perform better in PsA treatment. • The frequency of adverse events PsA and AS in comparison with the placebo group showed no difference. • Higher dose of tofacitinib could attain better treatment response without increasing adverse events in short-term follow-up.