Duodenal switch bested gastric bypass for weight loss

Søvik TT. Ann Intern Med. 2011;155:281-291.

Issue: October 2011

Patients who underwent biliopancreatic diversion with duodenal switch surgery lost more weight, experienced greater decreases in total and LDL cholesterol and had better body composition when compared with those who underwent gastric bypass surgery for severe obesity, new data suggest.

To compare outcomes from the two procedures, researchers at two medical centers in Norway and Sweden randomly assigned 60 participants with BMIs of 50 to 60 to undergo gastric bypass or duodenal switch. Follow-up occurred at 6-month intervals for 2 years after the procedure.

Participants in both study arms experienced considerable weight loss, but results favored the duodenal switch group, according to the researchers. At 24.8 (95% CI, 23-26.5), the mean decrease in BMI was significantly greater in the duodenal switch group compared with the gastric bypass group (17.3; 95% CI, 15.7-19). Actual weight loss was 73.5 kg (95% CI, 68.1-79) for the duodenal switch arm vs. 50.6 kg (95% CI, 45.4-55.8) for the gastric bypass arm. Likewise, mean percentage of body weight loss was higher for the duodenal switch group than for the gastric bypass group (44.8% vs. 31.2%).

Data also showed that, compared with those who had gastric bypass, participants who underwent duodenal switch exhibited greater reductions in total cholesterol (1.07 mmol/L vs. 0.24 mmol/L) and LDL cholesterol (0.78 mmol/L vs. 0.26 mmol/L). Decreases in sagittal diameter, waist and hip circumference, fat mass and fat-free mass were also significantly greater in the duodenal switch arm.

The frequency of adverse events, however, was also higher in the duodenal switch group. After 2 years, 32% of patients who had gastric bypass surgery vs. 62% of those who underwent duodenal switch experienced an adverse event (P=.021). Moreover, compared with 29% of gastric bypass patients, 41% of duodenal switch patients experienced a long-term adverse event.

Reductions in blood pressure, mean concentrations of glucose, insulin and C-reactive protein were similar between study arms, but decreases in vitamin A and 25-hydroxyvitamin D concentrations were noted in the duodenal switch group only, the researchers said. Health-related quality of life, as measured by Norwegian and Swedish versions of the Short Form-36 Health Survey, generally improved, with one domain, bodily pain, seeing greater improvement after gastric bypass.

"Data from our study suggest that superobese patients opting for gastric bypass should be informed that they are likely to experience clinically important health benefits even though they may expect to still be severely obese after surgery," the researchers wrote. "In contrast, duodenal switch provides greater weight loss and greater improvements in total and LDL cholesterol concentrations but at a potentially greater risk."

Disclosure: The study was funded by South-Eastern Norway Regional Health Authority.

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