Background: Weight reduction may reduce the severity of psoriasis, but little is known about the long-term effects.

Objective: We aimed to investigate long-term effects of weight reduction in psoriasis.

Design: We previously conducted a randomized trial (n = 60) involving patients with psoriasis who were allocated to a control group or a low-energy diet (LED) group. Here we followed the participants for an additional 48-wk period. In total, 56 patients with psoriasis [mean ± SD body mass index (in kg/m(2)): 34.4 ± 5.3] underwent a 64-wk weight-loss program consisting of an initial 16-wk randomized phase with an LED for 8 wk and 8 wk of normal food intake combined with 2 LED products/d, followed by a 48-wk period of weight maintenance with the latter diet. After the randomization phase, the control group received the same 8 + 8-wk LED intervention, and all patients were then followed for 48 wk while on the weight-loss maintenance diet. The main outcome was the Psoriasis Area and Severity Index (PASI), and secondary outcome was the Dermatology Life Quality Index (DLQI).

Results: For the present study, 56 patients were eligible, 38 agreed to participate, and 32 completed. After the 16-wk LED-only period, the mean weight loss was -15.0 kg (95% CI: -16.6, -13.4 kg), and PASI and DLQI were reduced by -2.3 (95% CI: -3.1, -1.5) and -2.3 (95% CI: -3.2, -1.4), respectively. At week 64, the mean weight loss compared with baseline was -10.1 kg (95% CI: -12.0, -8.1 kg), and PASI and DLQI were maintained at -2.9 (95% CI: -3.9, -1.9) and -1.9 (95% CI: -3.0, -0.9), respectively.

Conclusion: Long-term weight loss in patients with psoriasis has long-lasting positive effects on the severity of psoriasis. 

This trial was registered at clinicaltrials.gov as NCT01137188.