Background Psoriatic arthritis (PsA) patients have a higher prevalence of comorbidities including obesity, metabolic syndrome, depression and premature cardiovascular disease. There is evidence that obesity is associated with PsA. Obesity leads to increased proinflammatory cytokines which may contribute to the development of multiple disturbances in PsA patients. The relationship appears to be bidirectional as comorbidities seem to increase and perpetuate the proinflammatory status associated with adiposity.
Objectives A 12 month, randomized single blind clinical trial was conducted to determine whether long-term exercise and dietary weight loss are more efficacious, either separately or in combination, than standard care alone in improving physical function, pain, fatigue, depression and systemic inflammation in obese adults with PsA.
Methods Fifty-five obese ethnically homogenous adult PsA patients with a body mass index (BMI) ≥30, who satisfied the classification of psoriatic arthritis criteria were recruited. Patients were randomized into usual lifestyle (controls), diet only, exercise only, and diet plus exercise groups together with the continued use of standard treatment (NSAIDs, DMARDs and or anti-TNF alpha agents) for 12 months. Exclusion criteria included other inflammatory conditions. Detailed skin and rheumatological assessment was conducted. Disease activity was assessed by psoriasis area and severity index (PASI), disease activity score (DAS28CRP), Health Assessment Questionnaire- Disability Index (HAQ-DI), Beck's Depression Inventory (BDI) and fatigue numeric rating scale. Blood samples collected after 12 hours overnight fasting were analysed for glucose, lipid profile, ESR, hsCRP, proinflammatory cytokines; tumour necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-17 (IL-17). The primary outcome measures included improvement in ACR20, systemic inflammation markers, BMI, physical function, pain, fatigue, depression and HAQ-DI. Secondary endpoints included reduction in PASI score, DAS28-CRP response and physician and patient global assessment (PGA). Safety and tolerability were also assessed. Data was collected at baseline and every 6 months.
Results At 12 months the mean reduction in body weight was 15.0% in the intervention groups and was 2% in the control group, p=0.001. In the diet plus exercise group, there was significant improvement in ACR20, PASI, DAS28-CRP, BDI, fatigue, PGA and HAQ together with significant reductions in the serum levels of IL-6, TNF-alpha, hsCRP and IL-17 compared to controls. In the exercise group, there was significant improvement in ACR20, PASI, PGA, HAQ, BDI and fatigue. The diet only group showed significant reductions in systemic inflammatory markers and significant improvement in ACR20 and PASI75 response at 12 months. There was also a significant linear correlation between mean percent of body weight loss and PASI score reduction; r =0.587, p=0.002.
Conclusions Weight loss improved clinical outcomes and obesity-induced inflammation in PsA. Weight loss through diet and exercise induces a decrease in systemic inflammation and improves insulin sensitivity. Our data provides evidence that lifestyle modification supports traditional pharmacological approach in the treatment of obese PsA patients.
Disclosure of Interest None declared