Obesity is associated with multiple morbid conditions and a loss in life expectancy. Neither diet nor pharmacologic therapy is particularly effective; however, bariatric surgery is an additional treatment option. Buchwald and colleagues present the first systematic review of the impact of bariatric surgery on comorbid conditions, in particular, diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea.

Studies reporting outcomes of comorbid conditions after bariatric surgery were extracted. Weight loss and safety data also were examined. Outcome time points were assessed when outcomes were available for at least 50 percent of the patient population in the studies.

Weight loss ranged from 47.5 to 70.1 percent depending on the surgical technique used. Seventy-six percent or more of patients with diabetes had improvement or resolution of diabetes, depending on the study endpoint. Resolution was defined as discontinued need for diabetes medications and normalization of blood glucose levels. Patients with diabetes had significantly greater reductions in hemoglobin A1C and fasting glucose levels after bariatric surgery than did patients without diabetes. This effect was greatest for biliopancreatic diversion or duodenal switch procedures. Hyperlipidemia improved regardless of procedure type, with significant decreases in total cholesterol and low-density lipoprotein levels. Hypertension resolved in 61.7 percent of the total surgical population and resolved or improved in 78.5 percent, irrespective of surgical procedure. Significant improvements also were noted in sleep apnea, with 83.6 percent resolving or improving in the total population. Mortality as measured at 30 days or less after surgery was 0.1 to 1.1 percent, depending on the procedure.

The authors’ systematic review reveals that multiple morbidities improve or resolve in the majority of patients undergoing bariatric surgery. According to one large study, the overall rate of mortality after nine years was 9 percent in the surgical group compared with 28 percent in the control group. With some morbidities, specifically diabetes, the type of bariatric surgery made a difference in outcomes. Operative mortality was comparable with that of patients undergoing other major surgeries.

editor’s note: Ultimately, preventive measures carry the highest hope for managing obesity at the lowest cost. Meanwhile, this review shows that bariatric surgery is far more effective in treating obesity than diet, exercise, or pharmacologic management. Because of the high rate of morbidity and increased mortality associated with epidemic levels of obesity, a cost-benefit analysis is likely to favor surgical intervention. For those who are not candidates for bariatric surgery, recommendations for conventional weight loss goals are 10 percent of body weight. Patients should be told that a 10-kg (22-lb) weight loss results in multiple health benefits, including decreased angina, lower blood pressure, and lower lipid and blood sugar levels. The results, however, will not be nearly as dramatic as those cited here.—c.w.