Incidence of symptomatic gallstones after gastric bypass: is prophylactic treatment really necessary?

BACKGROUND: Because rapid weight loss after bariatric surgery increases gallstone formation, a 6-month treatment regimen with ursodiol has been recommended. Even prophylactic cholecystectomy at the time of gastric bypass in the absence of stones has been proposed. However, the incidence of symptomatic gallstones requiring cholecystectomy in untreated patients after gastric bypass has not yet been established.
METHODS: The patients in our study were not treated with ursodiol after open Roux-en-Y gastric bypass. Additional inclusion criteria were no palpable gallstones at bypass, at least 16 months of follow-up after bypass, and continuous coverage by the same health insurance plan extending from the time of the operation to study completion, to track subsequent cholecystectomies by claims paid.
RESULTS: A total of 100 females and 25 males met the study inclusion criteria. Follow-up extended from 16 to 48 months. Symptomatic gallstones requiring cholecystectomy developed in 10 patients, all females. Laparoscopic cholecystectomy was performed in 9 of these patients and open cholecystectomy was performed in the remaining patient, between 3 and 21 months after bypass. There were no serious complications from the stones or the cholecystectomy.
CONCLUSIONS: Prophylactic cholecystectomy would have been unnecessary in 115 of the 125 patients in the study group. A 6-month course of ursodiol for all 125 patients, at a cost of 56,250 dollars, would have had to decrease the number of cholecystectomies from 10 to 3 to demonstrate a treatment effect (P < .05). Therefore, most newly formed gallstones after gastric bypass are likely asymptomatic, prophylactic cholecystectomy is not indicated, and ursodiol therapy may be better reserved for symptomatic patients who refuse surgery.