Real-world Longterm Effectiveness of Tumor Necrosis Factor Inhibitors in Psoriatic Arthritis Patients from the Rheumatic Diseases Portuguese Register

Objective. To assess longterm effectiveness of tumor necrosis factor inhibitors (TNFi) in patients with psoriatic arthritis (PsA) registered in the Rheumatic Diseases Portuguese Register, exposed to at least 1 TNFi, prospectively followed between 2001 and 2017. Methods. Kaplan-Meier analysis was performed for first-, second-, and third-line TNFi. Responses included European League Against Rheumatism (EULAR) criteria, Disease Activity Index for Psoriatic Arthritis (DAPSA), minimal disease activity (MDA), and Ankylosing Spondylitis Disease Activity Score (ASDAS) at 3 and 6 months. Baseline predictors of discontinuation and response were studied using Cox and multivariable multinomial/logistic regression models. Results. The 750 patients with PsA showed drug retention of 4.1 +/- 3.4 years (followup 5.8 +/- 3.8 yrs) for first TNFi. Switching to a second (189 patients) or third (50 patients) TNFi further decreased survival by 1.1 years. Female sex, higher baseline 28-joint count Disease Activity Score, and infliximab were predictors of first TNFi discontinuation. After 6 months of the first TNFi, 48.7% of patients achieved a good EULAR criteria response and 20.9% were in DAPSA remission. There were 11.4% in MDA, and 56.4% had a good ASDAS. Responses to the second TNFi were significantly inferior compared to responses to the first TNFi. Female sex and higher baseline Health Assessment Questionnaire-Disability Index were negatively associated with good EULAR response at 3 months, and obesity decreased the chance of response at 6 months. Conclusion. In this study, switching to a second or third TNFi was associated with significantly lower drug survival and response rates for patients with axial and peripheral PsA subtypes. More successful therapeutic approaches will require considering the effect of sex and obesity on TNFi effectiveness.