A new study comparing the outcomes of obese patients undergoing bariatric surgery found that the less commonly used procedure known as the biliopancreatic diversion/duodenal switch (DS) resulted in better maintained weight loss and comorbidity control than the more popular gastric bypass (GB).
While the duodenal switch, a more drastic and technically challenging procedure than gastric bypass surgery, is also associated with higher early risks, including infection and the need for reoperation, the study authors say the absolute risk of complications is low.
Considering the outcome advantages of the duodenal switch as well as the significant number of patients who experience inadequate weight loss or weight gain after gastric bypass surgery, the researchers concluded the duodenal switch may be a viable option for carefully selected patients, especially the super-obese patients (Body Mass Index greater than 50).
About the Study
The researchers, led by Dr. Daniel Nelson of Madigan Army Medical Center in Fort Lewis, Washington, performed a retrospective review of the Bariatric Outcomes Longitudinal Database from 2007 to 2010, including all inpatient and outpatient data.
The analysis included outcomes of 1,545 patients who underwent biliopancreatic diversion/duodenal switch (DS) with an average BMI (Body Mass Index) of 52 and 77,406 patients who underwent gastric bypass (GB) with an average BMI (Body Mass Index) of 48. The average patient age was 45 and the majority of patients (more than three-quarters) were women.
The main outcome measures the researchers sought to compare were weight loss; control of comorbidities including diabetes mellitus, hypertension, and sleep apnea; and failure to achieve at least 50% excess body weight loss.
The researchers found that:
- The DS was associated with longer operative times (191 vs 114 minutes), greater blood loss, and longer lengths of hospital stay (2.4 vs 4.4 days)
- Nearly all GB procedures were performed laparoscopically, while half of DS procedures were performed with open surgery
- Reoperation rates were higher in DS patients (3.3% vs 1.5%)
- Percentage of change in BMI was significantly greater in DS patients at all follow-up intervals, reaching 43% for DS vs 36% for GB patients at 2 years
- In super-obese patients (BMI >50), percentage of excess body weight loss at 2 years was significantly greater in DS patients compared to GB patients, 79% vs 67%
- Comorbidity control of diabetes, hypertension, and sleep apnea was superior with the DS procedure
- The risk of weight loss failure was significantly reduced with DS vs GB for all patients, with a greater reduction in the super-obese group; 20% of GB patients failed to lose at least 50% of excess weight at 1 and 2 year follow-ups, compared to 9% and 6%, respectively, for DS patients
Although the duodenal switch has been slowly gaining attention in recent years, it still accounts for only a small percentage of bariatric surgeries performed. Researchers say reluctance to use the procedure is probably due to concerns over technical difficulties and potential long-term nutritional complications. They suggest “further studies of this procedure to determine the optimal patient selection, operative technique, and longer-term risks.”
The study, “Analysis of Obesity-Related Outcomes and Bariatric Failure Rates With the Duodenal Switch vs Gastric Bypass for Morbid Obesity,” authored by Daniel W. Nelson, DO; Kelly S. Blair, MD; and Matthew J. Martin, MD, was published in the September issue of the journal Archives of Surgery.
Comparing Surgical Procedures
Both the gastric bypass and duodenal switch procedure involve reducing the size of the stomach and bypassing a portion of the small intestine, though in different ways. Each procedure features a food restriction and malabsorption component, but food restriction is greater with the gastric bypass and malabsorption is greater with the duodenal switch.
With gastric bypass surgery, the top portion of the stomach is sectioned off into a new smaller stomach pouch and the intestines are divided and rerouted; the new digestive pathway bypasses the pyloric valve, which is the natural outlet between the stomach and small intestine, as well as the first portion of the small intestine; the bottom portion of the divided small intestine is attached to a new stomach opening (stoma) which was cut into the new smaller stomach pouch.
With duodenal switch, the stomach is sectioned off along the greater curvature leaving a “gastric sleeve,” reducing the size of the stomach and preserving the use of the pyloric valve. This allows for more normal digestion and prevents some of the complications associated with gastric bypass. The intestines are divided and rerouted to bypass a significant section of the digestive tract.
Both procedures cost about the same, generally ranging from $25,000 to $40,000, although insurance coverage is more likely for gastric bypass than duodenal switch.
Patients who are considering weight loss surgery should discuss all their options with an experienced bariatric surgeon. Choosing a procedure must take into account the different balance of potential risks versus potential benefits for each patient based on their own medical profile.
