THE EFFECT OF URSODEOXYCHOLIC ACID THERAPY ON GALLSTONE FORMATION IN THE MORBIDLY OBESE DURING RAPID WEIGHT-LOSS

Obesity is a significant risk factor for cholesterol gallstone formati on, particularly when patients are morbidly obese and rapidly losing w eight. Our objective, in a double-blind, placebo-driven trial of ursod eoxycholic acid, was to study the prevention of gallstone development in 29 morbidly obese subjects after bariatric surgery. These subjects included 20 women and nine men, ages 43 +/- 7.3 yr, weight 142.5 +/- 3 1 kg (mean +/- SD), representing 224% +/- 28.2% of their ideal body we ight. Gallbladders were free of stones according to preoperative ultra sound and palpation at surgery. Microscopy of aspirated gallbladder bi le revealed cholesterol crystals present in only one patient. After re covery from vertical-band gastroplasty, 13 patients received ursodeoxy cholic acid 1000 mg/day. Ten patients completed the 3-month study: two were noncompliant, one experienced heartburn. Fourteen of 16 subjects on matching placebo also were compliant; two were not. There were no differences in clinical characteristics or bile composition between th ese two groups on entry into the study. The cholesterol saturation ind ex in these obese patients at 1.62 +/- 0.46 was definitely supersatura ted, and higher than that in 10 non-obese patients without stones (0.9 6 +/- 0.29) or 10 with pigment stones (1.01 +/- 0.28) (p < 0.05). At 3 months, the two obese groups had similar weight loss (17% of preopera tive weight) and had repeat ultrasounds. Six of the 14 placebo-treated patients (43%) developed gallstones: two became symptomatic, requirin g cholecystectomy. There was no correlation between the risk of develo ping gallstones and pretreatment bile composition or the degree of wei ght loss. None of 10 patients on ursodeoxycholic acid formed gallstone s. Conclusions: Morbid obesity is associated with gallbladder bile sup ersaturated with cholesterol. A high percentage will develop gallstone s following gastroplasty. This can be prevented by ursodeoxycholic aci d therapy.