Weighing the Options With Bariatric Surgery: Long-Term Results Compare Risks, Health Outcomes

Evidence-Based Diabetes Management, April 2015, Volume 21, Issue SP5

A study published in JAMA Surgery compared long-term weight loss and other outcomes, along with adverse effects, of different surgical methods for weight loss.

Obesity has grown from a health concern to an epidemic, not just in the United States, but globally. Genetic, dietary, and environmental factors all play a role in the weight gain of obese individuals who suffer from numerous comorbidities, including type 2 diabetes mellitus (T2DM), cardiovascular disease, asthma, osteoarthritis, and cancer.1 The disease burden associated with these comorbidities translates into increasing expenditures that are a tremendous strain on the healthcare system.

A retrospective analysis, published in 2012 in the Journal of Occupational and Environmental Medicine, evaluated the incremental cost of smoking and obesity among employees and their dependents at the Mayo Clinic over a 7-year period.2 The study reported that both smoking and obesity resulted in excessive healthcare costs among the more than 30,000 individuals included in the study—smokers were responsible for an average of $1275 higher annual healthcare costs than non-smokers, while obese individuals cost an average of $1850 more than normal-weight individuals. Morbidly obese individuals, the study found, had substantially greater expenses: up to $5500 per year.2,3

Bariatric surgical procedures remain a proven method for weight loss among obese individuals who may have given up on the diet, exercise, and medication route. While Roux-en-Y gastric bypass (gastric bypass) and sleeve gastrectomy are both quite commonly performed in the United States,4 biliopancreatic bypass with a duodenal switch (duodenal switch) is performed in patients with a body mass index (BMI) greater than 50. However, a recent study published in JAMA Surgery found that the surgical procedure, performed laproscopically, resulted in higher rates of surgical, nutritional, and gastrointestinal adverse effects, even though the procedure produced more weight loss on average than gastric bypass.5


Studies have shown that as the prevalence of obesity has increased, surgical weight loss procedures have gained popularity, owing to expanded insurance coverage as well as improved perioperative safety.6 However, there is a reason why some procedures are more commonly performed than others, the authors of the JAMA Surgery study discovered.

In the study, which was a randomized open-label trial conducted at Oslo University Hospital in Norway, 60 patients aged between 20 and 50 years were recruited between early 2006 and late 2007. Fifty-ve of these patients, with a BMI between 50 and 60, were monitored for a 5-year period following the surgical procedure: either gastric bypass or duodenal switch. A shorter 2-year patient follow-up from this trial resulted in a series of publications that identied increased complications with duodenal switch, including gastrointestinal side effects and anal leakage of stool,7 malnutrition,8 and deciencies in vitamins A, B1, and D.9

However, weight loss and reduction in total and low-density lipoprotein (LDL) cholesterol were signicantly greater following duodenal switch than following gastric bypass.8 The 5-year follow-up, presented in the latest paper, evaluated the patients’ vitamin and nutritional status, gastrointestinal side effects, health-related quality of life (through a questionnaire), and other adverse events or complaints that they had. This longer-term study found that gastric bypass resulted in an average reduction in BMI of 13.6 (95% CI, 11.0-16.1) while duodenal switch resulted in an average reduction of 22.1 (95% CI, 19.5-24.7), which reiterated previously published results. Total body weight loss was 26.4% (95% CI, 21.7-31.1) after gastric bypass and 40.3% (95% CI, 35.7-44.9) after duodenal switch. The researchers did not observe a signicant difference in remission rates for T2DM and metabolic syndrome between the 2 patient cohorts. However, systolic blood pressure was much lower in both cohorts, while diastolic blood pressure was signicantly reduced only after gastric bypass. Effects on cardiometabolic risk factors such as total cholesterol and LDL cholesterol were sustained at 5 years following the duodenal switch surgery. However, patients undergoing duodenal switch expressed lower serum concentrations of vitamin A, 25-hydroxyvitamin D, and ionized calcium, and an increase in higher parathyroid hormone levels, compared with those in the gastric bypass cohort.5

Gastrointestinal adverse effects were much more severe following duodenal switch: while both groups reported increased abdominal pain and indigestion during follow-up, patients with duodenal switch had signicantly more diarrhea (though not statistically signicant; P = .07) and increased gastroesophageal reux (P = .002) compared with the gastric bypass patients. Further, social limitations due to altered bowel function were reported by 63% of duodenal switch patients and 25.9% of gastric bypass patients.5

While hospitalization for any reason was reported by 29% of gastric bypass patients and 58.6% of duodenal switch patients during the rst 5 years after surgery, 44.8% of duodenal switch patients had to undergo additional procedures related to the initial surgery versus 9.7% of gastric bypass patients.5

Overall, “Duodenal switch was associated with more surgical, nutritional, and gastrointestinal adverse effects compared with gastric bypass,” the authors concluded. In an accompanying commentary in the same issue of JAMA Surgery, 2 surgeons from the University of Michigan stress that the high rates of complications presented by the authors would restrict the employment of duodenal switch as a rst-line weight loss procedure. They recommend that patients should receive ample warning about risks associated with this surgery, and that the procedure should be reserved for compliant patients who are good with follow-up, to avoid the risk of fatal post operative complications.10


1. Guh DP, Zhang W, Bansback N, Amarsi Z, Birmingham CL, Anis AH. The incidence of comorbidities related to obesity and overweight: a systematic review and meta-analysis. BMC Public Health. 2009;9:88-107.

2. Moriarty JP, Branda ME, Olsen KD, et al. The effects of incremental costs of smoking and obesity on health care costs among adults: a 7-year longitudinal study. J Occup Environ Med. 2012;54(3):286-291.

3. Obesity adds more to health care costs than smoking, study suggests. ScienceDaily website. http://www.sciencedaily.com/releases/2012/04/120403124252.htm. Published April 3, 2012. Accessed February 19, 2015.

4. Buchwald H, Oien DM. Metabolic/bariatric surgery Worldwide 2008. Obes Surg. 2009;19:1605-1611.

5. Risstad H, Søvik TT, Engström M, et al. Five-year outcomes after laparoscopic gastric bypass and laparoscopic duodenal switch in patients with body mass index of 50 to 60: a randomized clinical trial [published online February 4, 2015]. JAMA Surg. doi:10.1001/jamasurg.2014.3579.

6. Reames BN, Finks JF, Bacal D, Carlin AM, Dimick JB. Changes in bariatric surgery procedure use in Michigan, 2006-2013. JAMA. 2014;312(9):959-961.

7. Søvik TT, Karlsson J, Aasheim ET, et al. Gastrointestinal function and eating behavior after gastric bypass and duodenal switch. Surg Obes Relat Dis. 2013;9(5):641-647.

8. Søvik TT, Aasheim ET, Taha O, et al. Weight loss, cardiovascular risk factors, and quality of life after gastric bypass and duodenal switch: a randomized trial. Ann Intern Med. 2011;155(5):281-291.

9. Aasheim ET, Björkman S, Søvik TT, et al. Vitamin status after bariatric surgery: a randomized study of gastric bypass and duodenal switch. Am J Clin Nutr. 2009;90(1):15-22.

10. Varban OA, Dimick, JB. Weighing the risks and benefits of bariatric surgery: choose your own adventure [published online February 4, 2015]. JAMA Surg. doi:10.1001/jamasurg.