Which method of bariatric surgery produces the greatest sustained weight loss?

Over the relative short term of 18 months -- the goal of obesity surgery is to prevent premature morbidity and mortality over 30 to 40 years -- gastric bypass surgery results in greater weight loss and fewer long-term complications than banding, though perioperative complications are higher and the surgery is more complicated. These results are based on low-quality studies; randomized controlled research is slow to permeate the surgery literature. Better studies in the future may find different results, and no study has followed up patients for longer than 5 years. (LOE = 2a)

Tice JA, Karliner L, Walsh J, Petersen AJ, Feldman MD. Gastric banding or bypass? A systematic review comparing the two most popular bariatric procedures. Am J Med 2008;121(10):885-893.  [PMID:18823860]

Meta-analysis (other)

Other

Various (meta-analysis)

Literature comparing the 2 main types of bariatric surgery, Roux-en-Y gastric bypass and laparoscopic gastric banding consists almost exclusively of retrospective comparisons. The researchers conducting this study searched 6 databases, including the Cochrane Library, searching for studies that compared the 2 types of surgery and their effect on patient-oriented outcomes -- weight loss, resolution of obesity-related illnesses, and mortality -- over a median of at least 19 months. Two researchers extracted the data independently. They identified 14 trials comparing the 2 approaches. The quality of the studies was low; only 1 study was a randomized controlled trial and it only enrolled 51 patients. The patients were approximately 40 years old and had an initial body mass index of 45 m/kg^2; 80% were women. Weight loss over 1 year was approximately 25% greater with gastric bypass; this difference was consistent across the studies. The authors did not combine the data, which is appropriate given the quality of the research. Two studies matched patients for age, body mass index, and comorbidities; in these studies, patients were more likely to experience resolution of the obesity-related comorbidities of diabetes, hypertension, dyslipidemia, and sleep apnea. Gastric bypass results in longer operative times, length of hospitalization, and early complications, but long-term complications occurred more frequently with gastric banding, including reoperation for port problems or slippage.