Roux-en-Y gastric bypass for morbid obesity: what are the preoperative predictors of weight loss?

Abstract

Obesity has become an increasingly important health problem over the past 30 years. Presently around a quarter of the UK adult population are obese and this figure is set to increase further in the coming decades. The health consequences of obesity on multiple body systems have been well established as has the financial cost of the condition to both the individuals affected as well as to society as a whole. Bariatric surgery has been shown to be the only long term effective solution in terms of sustained weight loss and comorbidity resolution. The commonest bariatric procedure in the UK is the Roux-en-y gastric bypass which consistently results in the loss of 70%-80% of excess bodyweight. Results however are variable and in order to optimise resource allocation and avoid exposing patients unlikely to benefit from surgery to its inherent risks, much research has been done to try to identify those patients most likely to obtain a good result. The only factor which has been subjected to meta-analysis is that of preoperative weight loss which shows a positive association with postoperative weight loss following bypass surgery. Although the remaining data are not based on level 1 evidence those other preoperatively identifiable factors which are associated with an improved outcome include Caucasian or Hispanic ethnicity, higher educational status, non-shift-work working patterns, female gender and divorced or single marital status. Similarly increased levels of preoperative physical activity and an absence of binge eating behaviour are consistent with a favourable result whereas increased age, smoking and other socioeconomic factors have not been shown to have a significant impact. Conversely diabetes mellitus seems to have a slight negative correlation with postoperative weight loss; however, a history of sexual abuse or psychiatric illness has not been shown to have a lasting influence.

Which Baseline Weight Should Be Preferred as Reference for Weight Loss Results? Insights in Bariatric Weight Loss Mechanisms by Comparing Primary and Revision Gastric Bypass Patients

“…Third, the revision group has significantly less patients with type 2 diabetes than the primary group. This comorbidity, however, is known to be a predictor for less favorable weight loss after bariatric surgery [14][15][16][17]. It is, therefore, unlikely that these differences concerning male gender and diabetes could have resulted in the opposite findings in this study.…”

Gender Influence on Long-Term Weight Loss and Comorbidities After Laparoscopic Sleeve Gastrectomy and Roux-en-Y Gastric Bypass: a Prospective Study With a 5-Year Follow-up

“…For example, while some authors report a positive relationship between T2DM and EBMIL% after bariatric surgery, others report a negative relationship [1,7]. Furthermore, other studies have reported a positive association between preoperative weight loss and EBMIL% after bariatric surgery [1,7,8].…”

Patient Factors Predicting Weight Loss after Roux-en-Y Gastric Bypass

“…Definition of successful weight loss varies among previous studies, with some using 40% EWL as a cutoff, [5, 12], whereas others use 50% EWL [6] and 60% EWL [7]. Perhaps a more important index of success is resolution of obesity related comorbidities and improvement in quality of life [8, 24]. Nevertheless, weight loss is the most easily measureable and frequently used parameter and a parameter that many patients consider to be very important.…”