Bariatric surgery appears to be more effective for weight loss and type 2 diabetes remission than nonsurgical interventions like diet and exercise, but the long-term effects remain uncertain, according to a new meta-analysis.
Researchers performed what they believed to be the first systematic review and meta-analysis of randomized, controlled trials that directly compared bariatric surgery with nonsurgical treatment. Included trials involved patients with a BMI of at least 30 kg/m2; reported data on body weight, cardiovascular risk factors, quality of life or adverse events; and had at least 6 months of follow-up. Eleven studies involving 796 patients with a mean BMI at baseline of 30 to 52 kg/m2 were included. The results were published online by BMJ Oct. 22.
Overall, patients who received bariatric surgery lost more weight, were more likely to have remission of type 2 diabetes, had greater improvements in quality of life, used less medicine, and had a greater decrease in waist circumference and triglyceride levels and a greater increase in high-density lipoprotein cholesterol levels than those who received nonsurgical interventions. Blood pressure changes and levels of total and low-density lipoprotein cholesterol levels did not differ according to whether patients received surgery or nonsurgical treatment. No patients were reported to have died or to have had cardiovascular events during follow-up. Fifteen percent of patients who had malabsorptive bariatric surgery developed iron-deficiency anemia, and 8% of patients had repeated surgery.
The authors concluded that compared with nonsurgical measures, bariatric surgery leads to more weight loss and higher remission rates of type 2 diabetes and the metabolic syndrome in obese patients. However, they also noted that their meta-analysis involved only 11 small trials with a maximum of 2 years’ follow-up. “The evidence beyond two years of follow-up, in particular on adverse events, cardiovascular diseases, and mortality remains unclear and calls for further research on the topic,” they wrote.