POS0212 COMPARISON OF PATIENT CHARACTERISTICS AND TREATMENT PATTERNS ACROSS BODY MASS INDEX CATEGORIES IN PATIENTS WITH PSORIATIC ARTHRITIS AND RHEUMATOID ARTHRITIS

Abstract

Background: Higher prevalence of obesity has been observed in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) versus the general population, and abnormal body mass index has been associated with worse rheumatic markers. Objectives: To describe PsA and RA patients in Switzerland, stratified by body mass index (BMI) category. Methods: We performed a descriptive cohort study in PsA and RA patients registered in the Swiss Clinical Quality Management in Rheumatic Diseases (SCQM) database. Two distinct cohorts were generated based on patient diagnosis (PsA or RA) and analysed separately but using similar approaches. In both cohorts, we included patients treated for the first time with biologics or targeted synthetic disease-modifying anti-rheumatic drugs (tsDMARDs), and considered the treatment start as index date. Patients without baseline BMI were excluded. Patients were stratified by BMI category at the start of biologic/tsDMARD treatment, defined as underweight (BMI<18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25.0-29.9), and obese (BMI≥30). In the PsA cohort, underweight and normal weight groups were merged due to low numbers. The proportion of patients categorized as overweight or underweight were compared to national statistics from the Swiss Federal Statistical Office. Information on patient demographics (e.g., age, sex, BMI, life-habits), disease-specific characteristics (e.g., disease activity scores, health questionnaires, biomarkers), co-medications and comorbidities were summarized at the start of the first biologic/tsDMARD treatment. Patient characteristics across BMI categories were compared, using the normal weight category as reference group. Additionally, we summarized the frequency and reasons for recorded treatment stop/switch at ≤6 months, 6 to 12 months, and >12months from treatment start, and illustrated the prescription patterns for first and second biologic/tsDMARD treatment, stratifying by BMI. Results: We identified 819 PsA [39.7% normal weight, 36.5% overweight, 23.8% obese] and 3217 RA patients [4.4% underweight, 46.8% normal weight, 31.8% overweight, 17.0% obese]. Figure 1 illustrates the prevalence of overweight and obesity in each cohort stratified by sex, compared to the national average. When comparing obese patients to those with normal weight, both PsA and RA obese patients had significantly higher C-reactive protein, worse disease activity score, lower quality of life (QoL) measures, and more frequent cardiovascular disease and diabetes. Among PsA patients, the overweight and obese had worse physician-assessed skin manifestation and patient-reported pain compared to the normal weight group. While in RA, the obese patients had higher erythrocyte sedimentation rate, smaller prevalence of seropositive patients, lower frequency of fractures/surgeries, and higher tender joint counts, but similar swollen joint counts, when compared to the normal weight group. Adalimumab and etanercept, were the most commonly prescribed drugs as first biologic/ tsDMARD treatment in both PsA and RA cohorts and among every BMI category. Overall, 55% PsA and 56% RA patients had recorded treatment stop/switch. Among RA patients, significantly fewer obese patients reported treatment stop/ switch at >12 months from treatment start, compared to the normal weight group. Adalimumab and etanercept were also the most commonly prescribed second biologic/tsDMARD treatment, but for the obese group among PsA patients (adalimumab, golimumab) and the obese group in the RA cohort (adalimumab, rituximab). Conclusion: In this national wide study, we observed that the prevalence of obesity in RA and PsA was higher than that of the general Swiss population. Obese PsA/RA patients starting first biologic/tsDMARD treatment presented worse disease activity and poorer QoL than normal weight patients. Results suggest to take BMI into consideration when treating PsA and RA patients.