Short-term treatment of weight loss with a very low-energy diet is associated with significant positive effects on disease activity in joints, entheses, and skin of patients with psoriatic arthritis (PsA) and obesity at 6 months, according to the results of a prospective, interventional study published in Arthritis Research & Therapy.

The investigators sought to prospectively evaluate the effects of weight loss treatment with a very low-energy diet on disease activity in patients with PsA based on Classification for Psoriatic Arthritis criteria and obesity (body mass index [BMI] ≥33 kg/m2). The participants consumed a very low-energy diet, defined as 640 kcal/d, over 12 to 16 weeks, based on their pre-treatment BMI. Following the very low-energy diet, an energy-restricted diet was reintroduced gradually. Treatment with conventional synthetic or biologic disease-modifying antirheumatic drugs was continued at the same dose from 3 months prior to and 6 months after baseline.

All patients were evaluated with BMI; 66/68 joints count; Leeds enthesitis index; psoriasis body surface area; C-reactive protein (CRP) level; and questionnaires at baseline, 3 months, and 6 months. The primary study outcome was percentage of patients achieving minimal disease activity (MDA). Secondary outcomes included attaining Psoriatic Arthritis Response Criteria (PsARC) and American College of Rheumatology (ACR) response criteria.

A total of 41 patients completed the study; 63% were women and median age was 54 years (interquartile range [IQR], 48 to 62 years). Increased BMI was linked to higher disease activity and poorer function at baseline.

Median weight loss was 18.7 kg (IQR, 14.6 to 26.5 kg), which corresponded to a loss of 18.6% in median baseline weight (IQR, 14.7% to 26.3%). Moreover, a majority of the disease activity parameters improved significantly following weight loss, which included 68/66 tender/swollen joint count, CRP level, body surface area, Health Assessment Questionnaire, and patient visual analog scale for pain, fatigue, and global health.

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It should be noted that a larger weight loss was associated with greater improvement in a dose-response fashion. The percentage of patients with MDA increased significantly from 29% to 54% (P =.002). PsARC was achieved in 46.3% of participants; ACR20 (20% improvement in ACR criteria), ACR50, and ACR70 responses were 51.2%, 34.1%, and 7.3%, respectively.

The investigators concluded that the study results support the hypothesis that obesity is involved in the pathophysiology of PsA. The very low-energy diet treatment used in this study was safe, effective, and well tolerated.

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Reference

Klingberg E, Bilberg A, Björkman S, et al. Weight loss improves disease activity in patients with psoriatic arthritis and obesity: an interventional study. Arthritis Res Ther. 2019;21(1):17.