Importance: Up to one-third of patients undergoing bariatric surgery have a body mass index (BMI) of more than 50. Following standard gastric bypass, many of these patients still have a BMI greater than 40 after peak weight loss.
Objective: To assess the efficacy and safety of standard gastric bypass vs distal gastric bypass in patients with a BMI of 50 to 60.
Design, setting, and participants: Double-blind, randomized clinical parallel-group trial at 2 tertiary care centers in Norway (Oslo University Hospital and Vestfold Hospital Trust) between May 2011 and April 2013. The study included 113 patients with a BMI of 50 to 60 aged 20 to 60 years. The 2-year follow-up was completed in May 2015.
Interventions: Standard gastric bypass (alimentary limb, 150 cm) and distal gastric bypass (common channel, 150 cm), both with a biliopancreatic limb of 50 cm and a gastric pouch of about 25 mL.
Main outcomes and measures: Primary outcome was the change in BMI from baseline until 2 years after surgery. Secondary outcomes were cardiometabolic risk factors, nutritional outcomes, adverse events, gastrointestinal symptoms, and health-related quality of life.
Results: At baseline, the mean age of the patients was 40 years (95% CI, 38-41 years), 65% were women, mean BMI was 53.5 (95% CI, 52.9-54.0), and mean weight was 158.8 kg (95% CI, 155.3-162.3 kg). The mean reduction in BMI was 17.8 (95% CI, 16.9-18.6) after standard gastric bypass and 17.2 (95% CI, 16.3-18.0) after distal gastric bypass, and the mean between-group difference was 0.6 (95% CI, -0.6 to 1.8; P = .32). Reductions in mean levels of total and low-density lipoprotein cholesterol were greater after distal gastric bypass than standard gastric bypass, and between-group differences were 19 mg/dL (95% CI, 11-27 mg/dL ) and 28 mg/dL (95% CI, 21 to 34 mg/dL), respectively (P < .001 for both). Reductions in fasting glucose levels and hemoglobin A1c were greater after distal gastric bypass. Secondary hyperparathyroidism and loose stools were more frequent after distal gastric bypass. The number of adverse events and changes in health-related quality of life did not differ between the groups. Importantly, 1 patient developed liver failure and 2 patients developed protein-caloric malnutrition treated by elongation of the common channel following distal gastric bypass.
Conclusions and relevance: Distal gastric bypass was not associated with a greater BMI reduction than standard gastric bypass 2 years after surgery. However, we observed different changes in cardiometabolic risk factors and nutritional markers between the groups.
Trial registration: Clinicaltrials.gov Identifier: NCT00821197.