Diet and weight loss as a treatment for psoriasis.

Question: Does moderate weight loss induced by a calorie-restrictive diet improve the therapeutic response to low dose cyclosporine in obese patients with moderate to severe psoriasis?

Design: A 24 week randomized controlled investigator blinded clinical trial.

Setting: Psoriasis outpatient clinic of the University Hospital of Verona.

Patients: Patients were 18 or older, had active but clinically stable plaque psoriasis involving ≥ 10% of the body surface area and a Psoriasis Area and Severity Index (PASI) of ≥ 10, and had a BMI of ≥30 but ≤45. Patients were excluded if they had other variants of psoriasis, had uncontrolled medical disorders, active or chronic infections, previous malignancies, previous treatment with cyclosporine or phototherapy or any systemic or topical therapy for psoriasis in the 4 weeks before enrollment.

Intervention: All patients were treated with 2.5mg/kg cyclosporine per day. Patients were randomized to receive a dietary intervention (low-calorie diet administered by a dietician) vs. no dietary intervention. The dietary intervention was a caloric restriction of 500 kcal below the calculated restring energy expenditure involving a diet of 60% carbohydrates, 25% fat, and 15% protein. All of the subjects were encouraged to exercise ≥40 minutes ≥4 times per week.

Main Outcome Measures: The primary endpoint was an improvement in PASI from baseline of ≥75% at week 24. Secondary endpoints were PASI 50 at week 24 and premature withdrawal from the study at week 24.

Results: 61 subjects were enrolled in the study. The baseline characteristics of the patients in terms of age, sex, BMI, waist circumference, PASI, and BSA affected were similar in both groups. The mean (+/-SD) weight loss and reduction in waist circumference was 7.0 +/- 3.5 kg and 3.5 +/- 2.7 cm and 0.2 +/- 0.9 kg and no reduction in waist size in the diet intervention group and the non-intervention group respectively. At week 24, PASI75 and 50 was achieved by significantly larger percentages of subjects in the diet intervention group, p<0.001 (see Table 1). The number of patients needed to treat with the dietary intervention plus cyclosporine to achieve one additional PASI75 responder over low dose cyclosporine alone was 3. In the intervention group, 4 patients (13.3%) dropped out due to adverse events associated with cyclosporine, whereas 14 patients (45.1%) dropped out in the non intervention group (10 because of lack of efficacy and 4 due to cyclosporine associated adverse events), p<0.001.

Conclusions: The authors conclude that obese patients with moderate to severe psoriasis increase their response to low-dose cyclosporine if a calorie controlled diet is included in the treatment regimen.