Prophylaxis against gallstone formation with ursodeoxyholic acid in patients participating in a very-low-calorie diet program. 

Objective: To determine whether prophylactic treatment with ursodeoxycholic acid can prevent gallstone formation in persons participating in a very-low-calorie weight reduction diet program.

Design: Multicenter, double-blind, placebo-controlled, multidose clinical trial. Patients were treated with placebo or with 300 mg/d, 600 mg/d, or 1200 mg/d of ursodeoxycholic acid.

Setting: Thirty-one Health Management Resources™ weight management centers.

Patients: 1004 patients were initially enrolled in a 16-week, 520-kcal/d, Health Management Resources liquid protein diet program. All patients had a body mass index of 38 kg/m² or more and a normal gallbladder ultrasonogram before study entry. Bile analysis was done in 32 patients.

Measurements: Body weight and body mass index were measured before the diet was started and at 2-week intervals for 16 weeks. Gallbladder ultrasonography was done before enrollment and after 8 and 16 weeks of dieting. Bile was obtained by endoscopy and analyzed for cholesterol crystals and lipid levels.

Results: Mean body weight for all patients at the start of dieting was 128.2 kg +/- 23.2 kg; mean initial body mass index was 44.2 kg/m² +/- 6.0 kg/m². Gallstones developed in 28% (95% CI, 22% to 35%) of patients receiving placebo, in 8% (CI, 5% to 13%) of patients treated with 300 mg/d of ursodeoxycholic acid, in 3% (CI, 1% to 7%) of patients treated with 600 mg/d of ursodeoxycholic acid, and in 2% (CI, 0.5% to 5%) of patients treated with 1200 mg/d of ursodeoxycholic acid. The differences between patients receiving placebo and patients receiving ursodeoxycholic acid were statistically significant. The percentage of ursodeoxycholic acid in bile increased stepwise with increasing doses of ursodeoxycholic acid.

Conclusions: Ursodeoxycholic acid, 600 mg/d, is highly effective in preventing gallstone formation in patients having dietary-induced weight reduction.