Population-based study of the need for cholecystectomy after obesity surgery.

BACKGROUND: Weight loss following obesity surgery is associated with gallstone formation, but there is limited evidence on whether prophylactic cholecystectomy is indicated during obesity surgery. The aim of this study was to clarify the need for cholecystectomy following obesity surgery. METHODS: A Swedish nationwide, population-based cohort study was conducted during the 22-year interval 1987-2008. Need for later cholecystectomy for gallstone disease was assessed in patients who had undergone obesity surgery in comparison with the general population of corresponding age, sex and calendar year. This need was also compared with the need for cholecystectomy in cohorts of patients who had undergone antireflux surgery and appendicectomy. Standardized incidence ratios (SIRs) with 95 per cent confidence intervals (c.i.) were calculated to estimate the relative risk. RESULTS: In the obesity surgery cohort of 13 443 patients, the observed number of cholecystectomies (1149, 8·5 per cent) exceeded the expected number by over fivefold (SIR 5·5, 95 per cent c.i. 5·1 to 5·8). The observed need for imperative cholecystectomy (for cholecystitis, cholangitis, pancreatitis, or jaundice; 427, 3·2 per cent) was also greater than expected (SIR 5·2, 4·7 to 5·7). The SIR peaked 7-24 months after obesity surgery and decreased with longer follow-up. The SIRs for cholecystectomy after antireflux surgery and appendicectomy were 2·4 (2·2 to 2·6) and 1·7 (1·6 to 1·7) respectively. CONCLUSION: An increased need for cholecystectomy after obesity surgery was confirmed, but was probably partly due to an increased detection of gallbladder disease only because of the surgery; the individual's risk of imperative cholecystectomy was low. Therefore, prophylactic cholecystectomy might not be recommended during obesity surgery.

Morbidity and mortality before and after bariatric surgery for morbid obesity compared with the general population.

BACKGROUND: Bariatric surgery reduces morbidity and mortality in obese subjects, but it is unclear how rates compare with those in the population. The aim was to assess the risk of admission to hospital for obesity-related co-morbidities and overall mortality after bariatric surgery in relation to the general population. METHODS: A nationwide, population-based cohort study was conducted of all patients who underwent bariatric surgery in Sweden between 1980 and 2006. Each patient was compared with ten age- and sex-matched controls randomly selected from the Total Population Register. Hospital admission for co-morbidities was identified through the Patient Register. Cox proportional regression was used to calculate hazard ratios (HRs). RESULTS: A total of 13 273 patients underwent bariatric surgery between 1980 and 2006. After surgery, the overall adjusted HR remained increased for myocardial infarction (HR 1·56, 95 per cent confidence interval 1·35 to 1·81), angina pectoris (HR 2·05, 1·84 to 2·31), stroke (HR 2·13, 1·88 to 2·42), hypertension (HR 2·80, 2·61 to 3·01), diabetes (HR 2·44, 2·23 to 2·67) and death (HR 1·24, 1·15 to 1·34) in these patients compared with the general population. The 4161 patients who underwent gastric bypass surgery no longer had a higher risk of diabetes (HR 1·23, 0·88 to 1·72) or myocardial infarction (HR 0·78, 0·42 to 1·45), whereas morbidity remained increased after restrictive surgery in 7855 patients. The adjusted mortality remained higher after both gastric bypass and restrictive surgery. CONCLUSION: Gastric bypass, but not restrictive surgery, in patients with morbid obesity seems to reduce the risk of diabetes and myocardial infarction to population levels, but the risk of death remains increased.