Failure to lose weight following gastric bypass surgery may be more common in males, older patients and African-Americans, according to a study presented recently at the American Society for Metabolic & Bariatric Surgery Annual Meeting in San Diego.
Researchers evaluated 1,096 patients who underwent gastric bypass and received 1 year or more of follow-up. Weight loss outcomes were compared between patients in the 75th percentile (n=218) and lower 25th percentile (n=232).
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After an average of 665 days, all patients lost a mean of 70% of their excess weight following the procedure. Investigators calculated the excess weight loss threshold as 82.4% for patients in the upper 75th percentile, compared with 57.4% in the lower 25th. Caucasians had a higher weight loss threshold (71.9%) compared with African-Americans (63.2%), and females (71%) had a higher threshold than males (63%).
Through multivariable regression, African-American race (OR=2.8; P=.001), advanced age (OR=0.967; P=.001), male sex (OR=0.302; P<.0005) and a higher initial BMI (OR=0.861; P<.0005) were all independently associated with failure to lose weight. Researchers found that this association continued when evaluating the 5th percentile, which included 42 patients and a weight loss threshold of 39.4%. Other potential predictive factors, including initial HbA1c levels, patient insurance and attending surgeon, were not found to be independently associated with failure.
A separate, nested case-control study also presented at the meeting evaluated 78 African-American women and 204 matched Caucasian controls who underwent laparoscopic Roux-en-Y gastric bypass (LRYGBP). Researchers found that the African-Americans had significantly less excess weight loss compared with controls after 4 years of follow-up (P<.001), though the two groups experienced similar remission rates (75% in African-Americans compared with 77% in controls). After adjusting for confounders, researchers found that type 2 diabetes was a predictor for adequate weight loss in the African-American cohort (adjusted OR=6.1E8, P<.002) at 3 years.
“Race significantly impacted the long-term excess weight loss at 4 years for patients undergoing [LRYGBP],” the researchers concluded. “Future research should be directed at determining potential genetic reasons for these differences, including genes associated with type 2 diabetes.”
For more information:
- Dallal RM. #PL-130: Predictors of Weight Loss Failure after Gastric Bypass Surgery. Presented at: the American Society for Metabolic & Bariatric Surgery Annual Meeting; June 17-22, San Diego.
Rodriguez J. #PL-112: Predictors of Long Term Success after Laparoscopic Roux-en-Y Gastric Bypass in African-American Women. Presented at: the American Society for Metabolic & Bariatric Surgery Annual Meeting; June 17-22, San Diego