Seeking an Initial-Weight-Independent Metric in a Mediterranean Cohort of Gastric Bypass Patients: the %AWL Revisited.

BACKGROUND: Most relative weight-loss metrics follow the formula "Weight loss(%) = 100 · (Initial BMI - Final BMI) / (Initial BMI-a)," where a is the reference point that defines the metric. The percentage of total weight loss (%TWL, a = 0) and percentage of excess weight loss (%EWL, a = 25) are influenced by a patient's initial weight. Recently, the percentage of alterable weight loss metric (%AWL, a = 13) has been reported to produce initial-weight-independent outcomes. OBJECTIVES: This study aimed to replicate the methodology used for %AWL determination in a Mediterranean cohort of bariatric patients. SETTINGS: Multicenter study in 10 large hospitals in Spain. METHODS: Two large prospective databases were retrospectively searched for all primary laparoscopic gastric bypass patients with 2 years of follow-up. Outcomes at nadir were expressed and analyzed with 26 different metrics (a from 0 to 25), looking for the metric whose outcomes produced (1) the lowest coefficient of variation, (2) no differences between initially lighter and heavier patients, and (3) no correlation with patients' initial BMI. RESULTS: A cohort of 1793 patients was stratified into 4 gender-age groups: younger women (YW, n = 733), older women (OW, n = 674), younger men (YM, n = 197), and older men (OM, n = 189). The calculations suggested an optimal reference point of 18 kg/m2, defining a new metric (percentage of Mediterranean alterable weight loss, %MAWL). When %TWL, %EWL, %AWL, and %MAWL were tested on the whole sample, only %MAWL produced initial-weight-independent results. CONCLUSIONS: In our Mediterranean cohort of patients, a reference point of 18 (and not 13) yielded initial-weight-independent outcomes.

Análisis de la pérdida ponderal a medio plazo después del bypass gastroyeyunal en Y de Roux y de la gastrectomía vertical: propuesta de gráficos de percentiles del porcentaje de peso total perdido para su uso en la práctica clínica diaria / Analysis of mid-term weight loss after Roux-en-Y gastric bypass and sleeve gastrectomy: Proposed percentile charts for total weight loss percentages to be used in daily clinical practice

Introducción: El objetivo de este trabajo es analizar la evolución ponderal de las principales técnicas quirúrgicas bariátricas (bypass gastroyeyunal en Y de Roux [BPGY] y gastrectomía vertical [GV]) realizadas en un conjunto representativo de centros nacionales españoles, con el fin de confeccionar unos gráficos de percentiles del porcentaje de pérdida total de peso perdido durante los 3 primeros años después de la cirugía. Métodos: Se realiza un estudio de cohortes longitudinal retrospectivo a partir de los datos aportados por 9 centros hospitalarios españoles. Se han analizado los datos ponderales tanto en porcentaje de pérdida total de peso perdido como en porcentaje de exceso de peso perdido correspondientes al BPGY (n = 1.887) y a la GV (n = 1.210). Resultados: El BPGY sigue siendo la técnica más frecuentemente realizada en nuestra muestra nacional. En ambas técnicas quirúrgicas, la pérdida de peso máxima se produce a los 18 meses de la cirugía. Ambas técnicas siguen la misma evolución ponderal, aunque los valores del porcentaje de pérdida total de peso perdido sean inferiores en el caso de la GV a los 36 meses (29,3 ± 10 vs. 33,6 ± 10). La edad y el género son determinantes en los resultados ponderales (mejores en paciente más jóvenes para ambas técnicas y mejores en mujeres para el BPGY). Conclusiones: Los gráficos de percentiles del porcentaje de peso total perdido después de la cirugía bariátrica representan una herramienta muy útil y un avance importante en la calidad asistencial para el seguimiento ponderal del paciente

Introduction: The aim of this study is to analyze weight evolution after the main bariatric surgical techniques (Roux-en-Y gastric bypass [RYGB] and sleeve gastrectomy [SG]) performed at a representative sample of Spanish hospitals in order to develop percentile charts for the percentage of total weight loss during the first 3 years after surgery. Methods: A retrospective longitudinal cohort study was conducted based on the data provided by 9 Spanish hospitals. Weight data were analyzed both in % total weight loss and % excess weight lost corresponding to the RYGB (n = 1,887) and SG (n = 1,210). Results: RYGB continues to be the most frequently performed technique in our sample. In both surgical techniques, maximum weight loss occurred 18 months after surgery. Both techniques followed the same weight evolution, although the % total weight loss values were lower in the case of the SG after 36 months (29.3 ± 10 vs. 33.6 ± 10). Age and gender are decisive in the weight results (better in younger patients for both techniques and better in women for RYGB). Conclusions: Percentile charts of % total weight loss after bariatric surgery represent a very useful tool and an important advance in the quality of patient management

Analysis of mid-term weight loss after Roux-en-Y gastric bypass and sleeve gastrectomy: Proposed percentile charts for total weight loss percentages to be used in daily clinical practice. / Análisis de la pérdida ponderal a medio plazo después del bypass gastroyeyunal en Y de Roux y de la gastrectomía vertical: propuesta de gráficos de percentiles del porcentaje de peso total perdido para su uso en la práctica clínica diaria.

INTRODUCTION: The aim of this study is to analyze weight evolution after the main bariatric surgical techniques (Roux-en-Y gastric bypass [RYGB] and sleeve gastrectomy [SG]) performed at a representative sample of Spanish hospitals in order to develop percentile charts for the percentage of total weight loss during the first 3 years after surgery. METHODS: A retrospective longitudinal cohort study was conducted based on the data provided by 9 Spanish hospitals. Weight data were analyzed both in % total weight loss and % excess weight lost corresponding to the RYGB (n=1,887) and SG (n=1,210). RESULTS: RYGB continues to be the most frequently performed technique in our sample. In both surgical techniques, maximum weight loss occurred 18 months after surgery. Both techniques followed the same weight evolution, although the % total weight loss values were lower in the case of the SG after 36 months (29.3±10 vs. 33.6±10). Age and gender are decisive in the weight results (better in younger patients for both techniques and better in women for RYGB). CONCLUSIONS: Percentile charts of % total weight loss after bariatric surgery represent a very useful tool and an important advance in the quality of patient management.

Weight Loss Analysis According to Different Formulas after Sleeve Gastrectomy With or Without Antral Preservation: a Randomised Study.

BACKGROUND: The measurement of weight loss after bariatric surgery is under constant review in order to obtain the ideal standard for reporting weight loss. Several formulas have been proposed for this purpose. Our goal is to analyse weight loss after sleeve gastrectomy, with or without antrum preservation through different measurement formulas. METHODS: A prospective randomised study of 60 patients (30 patients with initial section at 3 cm from pylorus and 30 patients at 8 cm from the pylorus). We calculate the following variables at 3, 6 and 12 months from surgery: BMI, excess weight loss (%EWL), percentage of excess of BMI loss (%PEBMIL), expected BMI, % PEBMIL corrected by EBMI and percentage of total weight loss (%TWL). RESULTS: Weight evolution is similar in both groups, reaching a mean BMI of 33.62 ± 4.35 and 34.48 ± 4.23 kg/m2 respectively 12 months after surgery, closer to expected BMI. TWL follows the same trend, with losses exceeding 30%, although 3 cm group is above the tables of percentiles made with our series. Regarding PEBMIL, the 3 cm group reaches 67.8% classified as excellent, while 8 cm group reaches 62.8% classified as a good result. EWL situates the best results for 3 cm group. CONCLUSIONS: Group 3 cm obtained a lower percentage of suboptimal results using EWL. %TWL places the 3 cm group in higher percentile than 8 cm group. Through EBMI, both groups are equally effective. It is necessary to have standardised dynamic tables for each surgical technique, becoming essential elements to measure weight loss after surgery.

Usefulness of Baltasar's expected body mass index as an indicator of bariatric weight loss surgery.

INTRODUCTION: Determining the best indicator to report weight loss takes on special relevance following bariatric surgery. Our objective is to apply a method proposed by Baltasar et al. to express weight loss results following bariatric surgery. MATERIALS AND METHODS: Anthropometric data were collected from 265 patients who had undergone Sleeve gastrectomy (SG, n = 172) and Roux-en-Y gastric bypass (RYGBP, n = 93) with a 2-year follow-up period. Initial BMI was calculated as well as BMI 2 years after, percentage of excess BMI loss (PEBMIL), expected BMI (EBMI), and corrected PEBMIL. RESULTS: In SG group, average BMI 2 years after surgery fell within a 95 % CI of expected BMI, with an average BMI of 31.58 ± 4.05 kg/m2 in 35-45 BMI group, an average BMI of 33.62 ± 4.96 kg/m2 in 45-55 BMI group, and an average BMI of 37.40 ± 5.93 kg/m2 in 55-65 BMI group. In RYGBP group, average BMI 2 years after the surgery was below than average expected BMI (28.76 ± 3.20 kg/m2 in 35-45 BMI group and 29.71 ± 3.30 kg/m2 in 45-55 BMI group). Results are considered excellent for the group with an initial BMI of above 45 kg/m2. CONCLUSIONS: EBMI is a good weight loss indicator, mainly when 95 % CI is taken into account. EBMI is consistent with the results obtained 2 years after surgery in our patients who underwent SG and RYGBP. Corrected PEBMIL is a good indicator for expressing the percentage of BMI loss and offers more realistic values than conventional formula with a cut-off point of 25 points.

Duodeno-jejunal tube placement in an experimental model of obesity: effects on food behaviour and basal energy expenditure.

BACKGROUND: Metabolic surgery can modulate weight as well as food intake and basal energy expenditure. In this study, we evaluate the effectiveness of duodenal exclusion by analysing anthropometric results, intake variations, food behaviour and calorimetric parameters. METHODS: This is an experimental study with 8-week-old Sprague-Dawley male rats. The sequences used are as follows: Cafeteria diet for 3 weeks, followed by surgery and sacrifice at 4 weeks. Four experimental groups are as follows: two non-obese groups (n = 15; surgery = 10, sham = 5) and two obese groups by cafeteria diet (n = 15; surgery = 10, sham = 5). Surgery performed was duodenal exclusion with physical barrier. Weight, intake, glycaemia and basal energy expenditure by indirect calorimetry were monitored before and after surgery. RESULTS: Weight changes in groups that underwent intervention were significant. The reduction in calorie consumption after surgery was significant in the obese intervention group despite an increased standard feed consumption (161 ± 11 vs 139 ± 13 Kcal/day, p < 0.05; due to a lower consumption of cafeteria diet). In non-obese animals, changes were transient. Basal energy expenditure decreased in both intervention groups: 6.2 ± 0.5 vs 5.5 ± 0.4 Kcal/kg/h in non-obese animals and 5.6 ± 0.3 vs 4.7 ± 0.3 Kcal/kg/h in obese animals (p < 0.05). CONCLUSIONS: Duodeno-jejunal tube placement stops weight gain in obese and non-obese animals. In obese animals, there is an important qualitative change in appetite towards standard feed with a significant decrease in caloric intake. In non-obese animals, changes in quantitative intake are transient. This surgery decreases basal energy expenditure in obese animals. This may be attributed to an enhanced thermogenic effect of food and a slowing in the animal's weight gain.