Association of Obesity with Higher Disease Activity and Lower Health-Related Quality of Life in Clinical Responders to Psoriatic Arthritis Treatment: Post-Hoc Analysis from the Spirit Studies

Objectives To investigate effects of overweight/obesity on health-related quality of life (HR-QoL) and disease activity among patients with psoriatic arthritis (PsA) who achieved American College of Rheumatology criteria (ACR50) or Disease Activity index for Psoriatic Arthritis (DAPSA) low disease activity (LDA).

Methods This post-hoc, unadjusted, treatment-agnostic analysis included PsA patients from the SPIRIT-P1, -P2, and -H2H studies who were treated with ixekizumab or adalimumab.[1] Patients achieving ACR50 or DAPSA LDA at week 24 (W24) were categorized based on baseline body mass index (BMI): Normal (<25 kg/m2), Overweight (25-<30 kg/m2), and Obesity (≥30 kg/m2). HR-QoL outcomes included Health Assessment Questionnaire-Disability Index (HAQ-DI) and fatigue severity numeric rating scale (NRS). Disease activity was evaluated using pain visual analog scale (VAS), swollen joint count (SJC), tender joint count (TJC), patient global assessment of disease activity (PatGA), physician global assessment of disease activity (PGA), and C-reactive protein (CRP). Observed data were presented. Non-parametric (Mann-Whitney U) test was used to account for non-normal distribution of some parameters; overweight or obesity subgroups were compared to the normal BMI subgroup; p<0.05 denoted statistical significance. No multiplicity testing adjustment was performed. The analysis was not adjusted for baseline assessments of HR-QoL or disease activity.

Results Among patients who achieved ACR50 by W24, significant differences were observed between obesity and normal BMI subgroups for HAQ-DI, fatigue severity NRS, pain VAS, and PatGA. CRP levels were significantly elevated for obesity and overweight vs the normal BMI subgroup (Table 1). Among patients who achieved DAPSA LDA by W24, patients with obesity had significantly higher fatigue severity NRS vs normal BMI subgroup. Pain VAS scores were significantly higher for the overweight vs normal BMI groups. Differences in PatGA and CRP were statistically significant between obesity and overweight vs normal BMI subgroup. HAQ-DI differences were not significant across BMI subgroups. No significant differences were observed in PGA, SJC, and TJC across BMI subgroups for patients achieving ACR50 or DAPSA LDA at W24.

Conclusion In patients with PsA who achieved stringent treatment targets of ACR50 and DAPSA LDA after 24 weeks of treatment, obesity/overweight is associated with some indicators of negative impact on PsA disease activity (pain, PatGA, CRP) and HR-QoL (fatigue, functional disability). These findings suggest that functional ability, HR-QoL, and other health outcomes in patients with PsA and obesity may be further improved by addressing comorbid obesity.

References [1.] Kristensen LE. Rheumatol Ther 2025;12:381-95.