Real-world skin and dermatology-specific quality-of-life outcomes and a nomogram to predict skin response to secukinumab in Chinese psoriatic arthritis patients: a multicenter retrospective cohort study

Background Real-world data on secukinumab in Chinese psoriatic arthritis (PsA) patients remain limited, particularly regarding short-term cutaneous response, dermatology-specific quality of life, and predictors of treatment response. Methods A retrospective cohort study was performed using 446 PsA patients diagnosed based on the Classification Criteria for Psoriatic Arthritis (CASPAR) criteria and treated with secukinumab for >12 weeks. Skin severity and quality of life were assessed using the Psoriasis Area and Severity Index (PASI), Body Surface Area (BSA), Investigator’s Global Assessment (IGA), and Dermatology Life Quality Index (DLQI) at baseline and after treatment. Treatment-related adverse events (TRAEs) were graded according to CTCAE v5.0. A predictive nomogram was constructed using stepwise multivariate regression and validated using the receiver operating characteristic (ROC) analysis. Results The cohort of 446 PsA patients (mean age 47.7 years; 65.2% men) exhibited significant improvements across all domains. Post-treatment PASI decreased from 14.2 ± 14.4 to 3.98 ± 8.84 ( p < 0.001), and DLQI improved from 11.9 ± 7.44 to 4.41 ± 5.63 ( p < 0.001). The correlation between PASI and DLQI significantly strengthened post-treatment ( R 2 increased from 0.34 to 0.52, Δ R 2 = +0.18; p < 0.001), accompanied by a steeper regression slope (0.3479 vs. 0.2229). Post-treatment objective-subjective outcome intercorrelations were robust (IGA-PASI r = 0.86, PASI-DLQI r = 0.62, all p < 0.001). A predictive nomogram incorporating five baseline variables — PASI score, disease duration, patient age, baseline BSA, and body mass index (BMI) — was developed and internally validated (AUC = 0.764, 95% CI: 0.712–0.816) for predicting cutaneous treatment response. Higher baseline PASI scores, longer disease duration, greater baseline BSA, older age, and lower BMI were associated with higher predicted probability of achieving treatment response. Conclusion In this real-world cohort of Chinese PsA patients, secukinumab demonstrates robust clinical short-term efficacy in skin severity and dermatology-specific quality of life, with a favorable short-term safety profile. The predictive nomogram may assist in estimating short-term cutaneous response, although external validation is required. However, these findings are specific to PsA patients and should not be extrapolated to psoriasis populations without musculoskeletal involvement, given the additional disease-burden dimensions in PsA that influence quality-of-life outcomes.