Incidence of symptomatic gallstones after bariatric surgery: the impact of expectant management.

BACKGROUND: Bariatric surgery is the most effective treatment for sustained weight reduction and obesity-related comorbidities. The development of gallstones as a result of rapid weight loss is a well-known consequence of bariatric procedures. It remains unclear, if there is an increased risk of these gallstones becoming symptomatic. METHODS: A retrospective analysis of 505 consecutive patients submitted to either Roux-en-Y Gastric Bypass or Sleeve Gastrectomy between January and December 2019 was performed. The aim of our study was to determine the incidence of symptomatic cholelithiasis in asymptomatic patients with their gallbladder in situ after bariatric surgery and to identify potential risk factors for its development. RESULTS: Of the 505 patients included, 79 (15.6%) underwent either previous cholecystectomy. (n = 67, 84.8%) or concomitant cholecystectomy during bariatric surgery (n = 12, 15.2%). Among the remaining 426 (84.4%) patients, only 8 (1.9%) became symptomatic during the 12-month follow-up period. When compared with patients who remained asymptomatic, they had a higher median preoperative BMI (47.0 vs. 42.8, p = 0.046) and prevalence of cholelithiasis on preoperative ultrasound (62.5% vs. 10.7%, p = 0.001). Multivariate analysis revealed preoperative BMI and cholelithiasis on preoperative ultrasound as independent risk factors for symptomatic biliary disease (OR 1.187, 95%CI 1.025-1.376, p = 0.022 and OR 10.720, 95%CI 1.613-71.246, p = 0.014, respectively). CONCLUSION: Considering a low incidence of symptomatic gallstones after bariatric surgery, concomitant cholecystectomy should only be performed in symptomatic patients undergoing bariatric surgery. Preoperative factors, such as a higher BMI and positive ultrasound for cholelithiasis, may be related to the development of symptomatic gallstones.

Accelerometry calibration in people with class II-III obesity: Energy expenditure prediction and physical activity intensity identification.

BACKGROUND: Almost all accelerometer calibration studies were developed for non-obese people, which hampers an accurate prediction of energy expenditure (EE) and induces a misclassification of sedentary activity (SA) and physical activity intensities (PAI) in class II-III obese people. RESEARCH QUESTION: The purpose of this study was to develop regression equations to predict EE and cut-points to classify SA and PAI in severe obese people based on several metrics obtained from hip and back accelerometer placement data. METHODS: 43 class II-III obese participants performed a protocol that included sitting and standing positions and walking at several speeds. During the protocol participants wore an accelerometer at hip and back, and respiratory gas exchange was measured by indirect calorimetry. Accelerometer metrics analyzed were: activity counts, mean amplitude deviation and euclidean norm minus one. EE was predicted through linear mixed models while cut-points to classify SA and PAI were obtained applying receiver operating characteristic curves. Leave-one-out cross-validation data was used to calculate Bland-Altman plots, prediction accuracy, Kappa statistic and percent agreement. RESULTS: All prediction models presented a quadratic equation that had as predictors body mass and one of the accelerometer metrics. Predicted EE indicated a good agreement and a root mean square error below 1.02 kcal min-1. Global classification agreement from developed cut-points was categorized as almost perfect with a percent agreement above 84 %. Prediction accuracy and classification agreement were similar among accelerometer metrics in each position and between them in hip and back placement. SIGNIFICANCE: Hip and back accelerometer data collected in severe obese people allow to accurately estimate EE and to correctly classify SA and PAI. These results enable future studies to adopt appropriate regression equations and cut-points developed for class II-III obese people rather than those established for non-obese people.

Gastric bypass is a cost-saving procedure: results from a comprehensive Markov model.

BACKGROUND: Obesity is a growing public health problem in industrialized countries and is directly and indirectly responsible for almost 10% of all health expenditures. Bariatric surgery is the best available treatment, however, associated with important economical expenditures. So, cost-effectiveness analysis of the available surgical options is paramount. METHODS: We developed a Markov model for three different strategies: best medical management, gastric band, and gastric bypass. The Markov model was constructed to allow for the evaluation of the impact of several obesity-related comorbidities. The results were derived for a representative population of morbidly obese patients, and subgroup analyses were performed for patients without comorbidities, patients with diabetes mellitus, different age, and body mass index (BMI) groups. Cost-effectiveness analysis was performed accounting for lifetime costs and from a societal perspective. RESULTS: Gastric bypass is a dominant strategy, rendering a significant decrease in lifetime costs and increase in quality-adjusted life years (QALYs). Comparing with the best medical management, in the global population of patients with a BMI of > 35 kg/m2, gastric bypass renders 1.9 extra QALYs and saves on average 13,244€ per patient. Younger patients, patients with a BMI between 40 and 50 kg/m2, and patients without obesity-related diseases are the ones with a bigger benefit in terms of cost effectiveness. CONCLUSIONS: Gastric bypass surgery increases quality-adjusted survival and saves resources to health systems. As such, it can be an important process to control the ever-increasing health expenditure.