Weight loss, cardiovascular risk factors, and quality of life after gastric bypass and duodenal switch: a randomized trial

BACKGROUND Gastric bypass and duodenal switch are currently performed bariatric surgical procedures. Uncontrolled studies suggest that duodenal switch induces greater weight loss than gastric bypass. OBJECTIVE To determine whether duodenal switch leads to greater weight loss and more favorable improvements in cardiovascular risk factors and quality of life than gastric bypass. DESIGN Randomized, parallel-group trial. (ClinicalTrials.gov registration number: NCT00327912) SETTING 2 academic medical centers (1 in Norway and 1 in Sweden). PATIENTS 60 participants with a body mass index (BMI) between 50 and 60 kg/m(2). INTERVENTION Gastric bypass (n = 31) or duodenal switch (n = 29). MEASUREMENTS The primary outcome was the change in BMI after 2 years. Secondary outcomes included anthropometric measures; concentrations of blood lipids, glucose, insulin, C-reactive protein, and vitamins; and health-related quality of life and adverse events. RESULTS Fifty-eight of 60 participants (97%) completed the study. The mean reductions in BMI were 17.3 kg/m(2) (95% CI, 15.7 to 19.0 kg/m(2)) after gastric bypass and 24.8 kg/m(2) (CI, 23.0 to 26.5 kg/m(2)) after duodenal switch (mean between-group difference, 7.44 kg/m(2) [CI, 5.24 to 9.64 kg/m(2)]; P < 0.001). Total cholesterol concentration decreased by 0.24 mmol/L (CI, -0.03 to 0.50 mmol/L) (9.27 mg/dL [CI, -1.16 to 19.3 mg/dL]) after gastric bypass and 1.07 mmol/L (CI, 0.79 to 1.35 mmol/L) (41.3 mg/dL [CI, 30.5 to 52.1 mg/dL]) after duodenal switch (mean between-group difference, 0.83 mmol/L [CI, 0.48 to 1.18 mmol/L]; 32.0 mg/dL [CI, 18.5 to 45.6 mg/dL]; P ≤ 0.001). Reductions in low-density lipoprotein cholesterol concentration, anthropometric measures, fat mass, and fat-free mass were also greater after duodenal switch (P ≤ 0.010 for each between-group comparison). Both groups had reductions in blood pressure and mean concentrations of glucose, insulin, and C-reactive protein, with no between-group differences. The duodenal switch group, but not the gastric bypass group, had reductions in concentrations of vitamin A and 25-hydroxyvitamin D. Most Short Form-36 Health Survey dimensional scores improved in both groups, with greater improvement in 1 of 8 domains (bodily pain) after gastric bypass. From surgery until 2 years, 10 participants (32%) had adverse events after gastric bypass and 18 (62%) after duodenal switch (P = 0.021). Adverse events related to malnutrition occurred only after duodenal switch. LIMITATION Clinical experience was greater with gastric bypass than with duodenal switch at the study centers. CONCLUSION Duodenal switch surgery was associated with greater weight loss, greater reductions of total and low-density lipoprotein cholesterol concentrations, and more adverse events. Improvements in other cardiovascular risk factors and quality of life were similar after both procedures. PRIMARY FUNDING SOURCE South-Eastern Norway Regional Health Authority.