Effect of weight loss on the severity of psoriasis: a randomized clinical study

IMPORTANCE Psoriasis is associated with adiposity and weight gain increases the severity of psoriasis and the risk of incident psoriasis. Therefore, we aimed to measure the effect of weight reduction on the severity of psoriasis in obese patients with psoriasis. OBJECTIVE To assess the effect of weight reduction on the severity of psoriasis in overweight patients. DESIGN Sixty obese patients with psoriasis from our dermatology outpatient clinic were enrolled in a prospective randomized clinical trial in which they were allocated to a control group or an intervention group. SETTING University hospital outpatient dermatology clinic. PARTICIPANTS We included 60 of 69 eligible overweight patients with psoriasis (body mass index [calculated as weight in kilograms divided by height in meters squared], 27-40; aged 25-71 years). INTERVENTIONS The intervention group received a low-energy diet (LED) (800-1000 kcal/d) for 8 weeks to induce weight loss, followed by 8 weeks of reintroduction of normal food intake, reaching 1200 kcal/d. The control group was instructed to continue eating ordinary healthy foods. MAIN OUTCOMES AND MEASURES Psoriasis Area and Severity Index (PASI) after 16 weeks, with Dermatology Life Quality Index (DLQI) as a secondary end point. RESULTS The median PASI for all patients was 5.4 (interquartile range, 3.8-7.6) at baseline. At week 16, the mean body weight loss was 15.4 kg (95% CI, 12.3-18.5 kg; P < .001) greater in the intervention group than in the control group. The corresponding mean differences in PASI and DLQI, also in favor of the LED group, were -2.0 (95% CI, 4.1 to -0.1; P = .06) and -2.0 (95% CI, -3.6 to -0.3; P = .02), respectively. CONCLUSIONS AND RELEVANCE Treatment with an LED showed a trend in favor of clinically important PASI improvement and a significant reduction in DLQI in overweight patients with psoriasis. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01137188.