Concomitant inflammatory bowel disease impairs biologic response and increases residual symptom burden in psoriatic arthritis

Objective: To investigate the impact of concomitant inflammatory bowel disease (IBD) on clinical response to biologic therapy in psoriatic arthritis (PsA). The primary aim was to identify predictors of achieving minimal disease activity (MDA) and DAPSA remission or low disease activity (LDA) at 6 months. Methods: We conducted a retrospective, matched cohort study of PsA patients initiating TNF inhibitors or anti-IL-12/23 agents between 2011 and 2023. Patients with (PsA-IBD) and without IBD (Only-PsA) were matched for age, sex, disease duration, and biologic class. Clinical assessments and patient-reported outcomes (PROs) were collected at baseline, 6, and 12 months. Multivariable logistic regression models were used to identify independent predictors of MDA and DAPSA remission/LDA at 6 months. Secondary outcomes included the proportion of patients achieving these targets over time and changes in disease activity scores and PROs. Results: A total of 120 PsA patients (60 PsA-IBD and 60 Only-PsA) were analyzed. At 6 months, MDA and DAPSA remission/LDA were achieved by 32.1 % and 50.0 % of PsA-IBD patients vs. 58.3 % and 78.3 % of Only-PsA patients (p = 0.005 and p = 0.008). IBD independently predicted lower odds of MDA (aOR 0.28, 95 % CI 0.11-0.69; p = 0.006) and showed a borderline association with reduced DAPSA response (aOR 0.39, 95 % CI 0.15-1.02; p = 0.055). At 12 months, PsA-IBD patients reported persistently higher VAS pain, PtGA, and HAQ-DI scores despite objective clinical improvements. Conclusion: Concomitant IBD is associated with impaired treatment response and greater residual symptom burden in PsA, underscoring the need for tailored therapeutic strategies in this challenging phenotype.