Gastric bypass surgery is more effective for weight loss and long-term weight maintenance than are other surgical procedure or non-surgical treatment, according to a US analysis.
Led by researchers at Duke Health and the Durham VA Medical Centre, the study’s findings are based on the analysis of ten years of medical records for veterans who underwent one of three different weight-loss surgery procedures at VA medical centres or community hospitals reimbursed by the VA.
“Very few studies have shown how weight-loss surgery patients change over the long term, which we consider a period of five years or more,” said lead author Dr Matthew Maciejewski, a professor of medicine at Duke and director of the Health Economics and Policy Unit at the Durham VA Medical Centre.
“We also wanted to contribute to filling the evidence gap about the comparative outcomes of the different forms of weight-loss surgery,” Maciejewski said. In the study’s first part, Maciejewski and co-investigators compared the records of 1,787 veterans who underwent gastric bypass to the records of 5,305 veterans who did not have any form of weight loss surgery. These non-surgical patients were included in the study based on several criteria – including age, sex, race, chronic conditions, and body mass index (BMI) – to compare their experiences with weight to those of the bariatric surgery patients.
After one year, patients undergoing Roux-en-Y gastric bypass lost 31% of their baseline weight, while the non-surgical patients lost 1.1% of their baseline weight, making for a nearly 30% greater weight loss among surgical patients. The study team also found that the gastric bypass patients had maintained a nearly 21% greater weight loss then their non-surgical counterparts after 10 years.
In the second part of the study, the study team compared weight change four years after surgery for 246 patients who underwent adjustable gastric banding (AGB); 1,785 who underwent gastric bypass; and 379 who underwent sleeve gastrectomy (SG). The latter two procedures have become common forms of bariatric surgery in recent years and sleeve gastrectomy is a relatively new procedure, so the study team could only examine outcomes for a four-year period.
The study team found that the gastric bypass patients saw the most weight loss in each year. At year four, gastric bypass patients had lost 27.5% of their baseline weight, while AGB patients lost 10.6% and SG patients lost 17.8%.
“The results indicate that bariatric surgery, especially gastric bypass, provides significant long-term health benefits in terms of dramatic and sustained weight loss up to ten years after surgery,” Maciejewski said. “Patients, clinicians and policymakers should feel confident that gastric bypass can induce sustainable weight loss,” he added.
The authors note that the patients in the study were predominantly male and about five years older than the typical bariatric surgery patient seen outside of VA hospitals. Additionally, in the absence of standardised weight measurements for patients, researchers used model-estimated predictions for certain time points.
Importance: Bariatric surgery induces significant weight loss for severely obese patients, but there is limited evidence of the durability of weight loss compared with nonsurgical matches and across bariatric procedures.
Objectives: To examine 10-year weight change in a large, multisite, clinical cohort of veterans who underwent Roux-en-Y gastric bypass (RYGB) compared with nonsurgical matches and the 4-year weight change in veterans who underwent RYGB, adjustable gastric banding (AGB), or sleeve gastrectomy (SG).
Design, Setting, and Participants: In this cohort study, differences in weight change up to 10 years after surgery were estimated in retrospective cohorts of 1787 veterans who underwent RYGB from January 1, 2000, through September 30, 2011 (573 of 700 eligible [81.9%] with 10-year follow-up), and 5305 nonsurgical matches (1274 of 1889 eligible [67.4%] with 10-year follow-up) in mixed-effects models. Differences in weight change up to 4 years were compared among veterans undergoing RYGB (n = 1785), SG (n = 379), and AGB (n = 246). Data analysis was performed from September 9, 2014, to February 12, 2016.
Exposures: Bariatric surgical procedures and usual care.
Main Outcomes and Measures: Weight change up to 10 years after surgery through December 31, 2014.
Results: The 1787 patients undergoing RYGB had a mean (SD) age of 52.1 (8.5) years and 5305 nonsurgical matches had a mean (SD) age of 52.2 (8.4) years. Patients undergoing RYGB and nonsurgical matches had a mean body mass index of 47.7 and 47.1, respectively, and were predominantly male (1306 [73.1%] and 3911 [73.7%], respectively). Patients undergoing RYGB lost 21% (95% CI, 11%-31%) more of their baseline weight at 10 years than nonsurgical matches. A total of 405 of 564 patients undergoing RYGB (71.8%) had more than 20% estimated weight loss, and 224 of 564 (39.7%) had more than 30% estimated weight loss at 10 years compared with 134 of 1247 (10.8%) and 48 of 1247 (3.9%), respectively, of nonsurgical matches. Only 19 of 564 patients undergoing RYGB (3.4%) regained weight back to within an estimated 5% of their baseline weight by 10 years. At 4 years, patients undergoing RYGB lost 27.5% (95% CI, 23.8%-31.2%) of their baseline weight, patients undergoing AGB lost 10.6% (95% CI, 0.6%-20.6%), and patients undergoing SG lost 17.8% (95% CI, 9.7%-25.9%). Patients undergoing RYGB lost 16.9% (95% CI, 6.2%-27.6%) more of their baseline weight than patients undergoing AGB and 9.7% (95% CI, 0.8%-18.6%) more than patients undergoing SG.
Conclusions and Relevance: Patients in the Veterans Administration health care system lost substantially more weight than nonsurgical matches and sustained most of this weight loss in the long term. Roux-en-Y gastric bypass induced significantly greater weight loss among veterans than SG or AGB at 4 years. These results provide further evidence of the beneficial association between surgery and long-term weight loss that has been demonstrated in shorter-term studies of younger, predominantly female populations.
Matthew L Maciejewski; David E Arterburn; Lynn Van Scoyoc; Valerie A Smith; William S Yancy Jr; Hollis J Weidenbacher; Edward H. Livingston; Maren K Olsen