title: Impact of rapid weight reduction on risk of cholelithiasis after bariatric surgery.
abstract: BACKGROUND
  Obesity alone and rapid weight loss induced by bariatric surgery are recognized risk factors for the development of cholelithiasis. The decision to perform prophylactic cholecystectomy at the time of bariatric operations remains controversial and at the surgeon's discretion.
  
  
  METHODS
  From June 1998 to April 2001, 103 patients underwent Roux-en-Y gastric bypass (RYGBP) in Hospital das Clinicas/Unicamp (SP). 88 of these 103 patients had their preoperative ultrasonography of gallbladder recovered. 19 of these 88 patients showed gallstones before RYGBP, and the remaining 69 did not have ultrasonographic evidence of cholelithiasis. 36 of these 69 patients were followed with ultrasonography during the 12 postoperative months. They were divided into 2 groups: those who formed gallstones (n=19) and those who did not (n=17), to evaluate the importance of sex, age, preoperative BMI, preoperative excess weight and postoperative percent excess weight loss as risk factors in the gallstone formation.
  
  
  RESULTS
  Preoperative incidence of cholelithiasis in the 88 operated patients was 21.6% and postoperative incidence in the 36 patients followed by ultrasonograph was 52.8%. There was no statistical evidence that postoperative gallstone formation is associated significantly with the variables studied.
  
  
  CONCLUSIONS
  This study confirms the high correlation between morbid obesity, rapid weight loss and gallbladder disease. Predictive risk factors for gallstone formation were not found.
authors.affiliation: Center for Surgical Treatment of Obesity, Faculdade de Ciências Médicas, Unicamp, Campinas, SP, Brazil. cibo@uol.com.br
authors.forename: Carlos
authors.initials: C
authors.lastname: Iglézias Brandão de Oliveira
authors.forename: Elinton
authors.initials: E
authors.lastname: Adami Chaim
authors.forename: Benedito Borges
authors.initials: BB
authors.lastname: da Silva
mesh_terms: D000328:Adult; D000367:Age Factors; D000713:Anastomosis, Roux-en-Y / Q000009:adverse effects*; D015992:Body Mass Index; D002769:Cholelithiasis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors; D014463:Ultrasonography; D015431:Weight Loss