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Background: Obesity affects 32% of adults in the USA. Surgery generates substantial weight loss, but 20-30% fails to achieve successful weight loss. Our objective was to identify preoperative psychosocial factors associated with weight loss following bariatric surgery., Methods: We performed a literature search of PubMed® and the Cochrane Database of Reviews of Effectiveness between 1988 and April 2010. Articles were screened for bariatric surgery and weight loss if they included a preoperative predictor of weight loss: body mass index (BMI), preoperative weight loss, eating disorders, or psychiatric disorder/substance abuse. One thousand seven titles were reviewed, 534 articles screened, and 115 included in the review., Results: Factors that may be positively associated with weight loss after surgery include mandatory preoperative weight loss (7 of 14 studies with positive association). Factors that may be negatively associated with weight loss include preoperative BMI (37 out of 62 studies with negative association), super-obesity (24 out of 33 studies), and personality disorders (7 out of 14 studies). Meta-analysis revealed a decrease of 10.1% excess weight loss (EWL) for super-obese patients (95% confidence interval (CI) [3.7-16.5%]), though there was significant heterogeneity in the meta-analysis, and an increase of 5.9% EWL for patients with binge eating at 12 months after surgery (95% CI [1.9-9.8%])., Conclusions: Further studies are necessary to investigate whether preoperative factors can predict a clinically meaningful difference in weight loss after bariatric surgery. The identification of predictive factors may improve patient selection and help develop interventions targeting specific needs of patients.

Social support may be associated with increased weight loss after bariatric surgery. The objective of this article is to determine impact of post-operative support groups and other forms of social support on weight loss after bariatric surgery. MEDLINE search (1988-2009) was completed using MeSH terms including bariatric procedures and a spectrum of patient factors with potential relationship to weight loss outcomes. Of the 934 screened studies, 10 reported on social support and weight loss outcomes. Five studies reported on support groups and five studies reported on other forms of social support (such as perceived family support or number of confidants) and degree of post-operative weight loss (total n = 735 patients). All studies found a positive association between post-operative support groups and weight loss. One study found a positive association between marital status (being single) and weight loss, while three studies found a non-significant positive trend and one study was inconclusive. Support group attendance after bariatric surgery is associated with greater post-operative weight loss. Further research is necessary to determine the impact of other forms of social support. These factors should be addressed in prospective studies of weight loss following bariatric surgery, as they may represent ways to improve post-operative outcomes., (© 2010 The Authors. obesity reviews © 2010 International Association for the Study of Obesity.)

Patients undergoing bariatric surgery lose substantial weight (> or = 50% excess weight loss [EWL]), but an estimated 20 per cent fail to achieve this goal. Our objective was to identify behavioral predictors of weight loss after laparoscopic Roux-en-Y gastric bypass. We retrospectively surveyed 148 patients using validated instruments for factors predictive of weight loss. Success was defined as > or =50 per cent EWL and failure as <50 per cent EWL. Mean follow-up after laparoscopic Roux-en-Y gastric bypass was 40.1 +/- 15.3 months, with 52.7 per cent of patients achieving successful weight loss. After controlling for age, gender, and preoperative body mass index, predictors of successful weight loss included surgeon follow-up (odds ratio [OR] 8.2, P < 0.01), attendance of postoperative support groups (OR 3.7, P = 0.02), physical activity (OR 3.5, P < 0.01), single or divorced marital status (OR 3.2, P = 0.03), self-esteem (OR 0.3, P = 0.02), and binge eating (OR 0.9, P < 0.01). These factors should be addressed in prospective studies of weight loss after bariatric surgery, as they may identify patients at risk for weight loss failure who may benefit from early tailored interventions.

The contribution of physical activity on the degree of weight loss following bariatric surgery is unclear. To determine impact of exercise on postoperative weight loss. Medline search (1988-2009) was completed using MeSH terms including bariatric procedures and a spectrum of patient factors with potential relationship to weight loss outcomes. Of the 934 screened articles, 14 reported on exercise and weight loss outcomes. The most commonly used instruments to measure activity level were the Baecke Physical Activity Questionnaire, the International Physical Activity Questionnaire, and a variety of self-made questionnaires. The definition of an active patient varied but generally required a minimum of 30 min of exercise at least 3 days per week. Thirteen articles reported on exercise and degree of postoperative weight loss (n = 4,108 patients). Eleven articles found a positive association of exercise on postoperative weight loss, and two did not. Meta-analysis of three studies revealed a significant increase in 1-year postoperative weight loss (mean difference = 4.2% total body mass index (BMI) loss, 95% confidence interval (CI; 0.26-8.11)) for patients who exercise postoperatively. Exercise following bariatric surgery appears to be associated with a greater weight loss of over 4% of BMI. While a causal relationship cannot be established with observational data, this finding supports the continued efforts to encourage and support patients' involvement in post-surgery exercise. Further research is necessary to determine the recommended activity guidelines for this patient population.

Background: Preoperative weight loss before bariatric surgery has been proposed as a predictive factor for improved patient compliance and the degree of excess weight loss achieved after surgery. In the present study, we sought to determine the effect of preoperative weight loss on postoperative outcomes., Methods: A search of MEDLINE was completed to identify the patient factors associated with weight loss after bariatric surgery. Of the 909 screened reports, 15 had reported on preoperative weight loss and the degree of postoperative weight loss achieved. A meta-analysis was performed that compared the postoperative weight loss and perioperative outcomes in patients who had lost weight preoperatively compared to those who had not., Results: Of the 15 articles (n = 3404 patients) identified, 5 found a positive effect of preoperative weight loss on postoperative weight loss, 2 found a positive short-term effect that was not sustained long term, 5 did not find an effect difference, and 1 found a negative effect. A meta-analysis revealed a significant increase in the 1-year postoperative weight loss (mean difference of 5% EWL, 95% confidence interval 2.68-7.32) for patients who had lost weight preoperatively. A meta-analysis of other outcomes revealed a decreased operative time for patients who had lost weight preoperatively (mean difference 23.3 minutes, 95% confidence interval 13.8-32.8)., Conclusion: Preoperative weight loss before bariatric surgery appears to be associated with greater weight loss postoperatively and might help to identify patients who would have better compliance after surgery.