Concurrent initiation of tirzepatide and biologics improves patient-reported outcomes in obese psoriatic arthritis: a propensity score-matched study.

OBJECTIVE: To evaluate 6-month clinical outcomes in obese patients with psoriatic arthritis (PsA) who initiated tirzepatide concurrently with biologic therapy compared with those starting biologics alone. METHODS: Propensity score-matched comparative study at tertiary care rheumatology centres. Patients with PsA with body mass index (BMI) ≥30 kg/m² or ≥27 kg/m² with at least one weight-related comorbidity initiating tirzepatide (2.5 mg/week, uptitrated to 5 mg/week after 1 month) with biologic therapy were prospectively enrolled from January 2025. Controls initiating biologics alone (2021-2025) were matched 1:2 on BMI, disease duration, Disease Activity Index for Psoriatic Arthritis (DAPSA) and Psoriasis Area and Severity Index (PASI). Outcomes at 6 months included minimal disease activity, DAPSA low disease activity (≤14), PsA Impact of Disease-12 (PsAID-12) Patient Acceptable Symptom State (PASS ≤4), Health Assessment Questionnaire (HAQ ≤0.5), PASI ≤1, Visual Analogue Scale pain and C reactive protein (CRP). Continuous outcomes were additionally analysed with ANCOVA adjusted for baseline and a mixed (time × group) model. RESULTS: Thirty-one patients completed 6 months and were matched to 62 controls. Baseline characteristics were well balanced. The tirzepatide group showed greater BMI reduction (-2.9±2.0 vs +0.4±1.2 kg/m², p<0.001) and lower CRP (4.2±3.8 vs 7.7±3.0 mg/L, p<0.001). PsAID-12 PASS was achieved by 48% vs 21% (OR 3.44, 95% CI 1.38 to 8.63, p=0.009), HAQ≤0.5 by 42% vs 18% (OR 3.27, 95% CI 1.26 to 8.44, p=0.022) and PASI≤1 by 74% vs 52% (OR 2.59, 95% CI 1.03 to 6.56, p=0.045). Baseline-adjusted ANCOVA confirmed significant 6-month differences in favour of tirzepatide for BMI, CRP, PsAID-12 and DAPSA, with a significant time × group interaction for BMI, CRP and PsAID-12. CONCLUSION: Concurrent tirzepatide and biologic initiation in obese PsA was associated with significantly better patient-reported outcomes, skin disease control, baseline-adjusted joint disease activity and CRP reduction at 6 months.