Comparison between total weight loss and other metrics after bariatric surgery using a multilevel mixed-effects linear regression model.

BACKGROUND: Several tools are used to assess postoperative weight loss after bariatric surgery, including the percentage of excess body weight loss (%EWL), percentage of total weight loss (%TWL), and percentage of excess body mass index (BMI) loss (%EBMIL). A repeated series of measurements should be considered to assess weight loss as accurately as possible. This study aimed to test weight loss metrics. METHODS: Data were obtained from a prospective database of patients with obesity who underwent laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) between 2016 and 2017 in a French tertiary referral bariatric center. A multilevel mixed-effects linear regression model with repeated measures was used to analyze repeated weight measurements over time. RESULTS: A total of 435 patients underwent LRYGB (n = 266) or LSG (n = 169). At 2 years, the average %EWL, %EBMIL, and %TWL were 56.8%, 61.3%, and 26.6%, respectively. Patients who underwent LSG experienced lower weight loss (ß: - 4233 in %TWL model, ß: - 6437 in %EWL model, and ß: - 6989 in %EBMIL model) than those who underwent LRYGB. In multivariate mixed analysis, preoperative BMI was not significantly associated with %TWL at 2 years (ß, - 0.09 [- 0.22-0.03] p = 0.1). Preoperative BMI was negatively associated with both %EWL (ß, - 1.61 [- 1.84-- 1.38] p < 0.0001) and %EBMIL (ß, - 1.91 [- 2.16-- 1.66] p < 0.0001). CONCLUSION: This is the first study to assess %TWL use for postoperative weight measurement, using a multilevel mixed-effects linear regression model %TWL is the measure of choice to assess weight loss following bariatric surgery.

Laparoscopic Sleeve Gastrectomy versus Laparoscopic Roux-en-Y Gastric Bypass: An Analysis of Weight Loss Using a Multilevel Mixed-Effects Linear Model.

BACKGROUND: Regarding weight loss outcomes, the results published after laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y (LRYGB) are conflicting. At this time, no clear evidence exists that outcomes from LSG are similar to those for LRYGB. The main objective of this study was to compare the percent of total weight loss (%TWL) between LRYGB and LSG over the first 2 years using a multilevel mixed-effects linear regression. METHODS: Data were collected from a prospectively maintained database of patients who underwent primary laparoscopic bariatric surgery from January 2016 to December 2017 at a French accredited bariatric center. The medical records of 435 consecutive patients were analyzed. %TWL was calculated at each follow-up surgical consultation and used as a repeated outcome variable in our models to assess the long-term %TWL. Due to this hierarchical structure of the data (%TWL at each visit = level 1) within patients (level 2), a multilevel linear regression adjusted for age, sex, preoperative BMI and comorbidities was used. RESULTS: Among the medical records of 435 consecutive patients included, 266 patients underwent LRYGB and 169 underwent LSG. The average %TWL at 2 years was 31.7% for the LRYGB group and 25.8% for the LSG group. The final multivariate model showed that, compared with LRYGB, LSG was associated with a decreased %TWL at over 2 years of follow-up (ß: -4.01; CI95%: -5.47 à -2.54; p ≤ 0.001). CONCLUSION: This observational study suggests that compared with LRYGB, LSG was associated with a decreased %TWL at 2 years using a multilevel model. Further studies are required to confirm the results observed with this statistical model.

Are Geographical Health Accessibility and Socioeconomic Deprivation Associated with Outcomes Following Bariatric Surgery? A Retrospective Study in a High-Volume Referral Bariatric Surgical Center.

PURPOSE: Few studies have evaluated the association between non-clinical determinants (socioeconomic status and geographic accessibility to healthcare) and the outcomes of bariatric surgery, with conflicting results. This study aimed to evaluate this association. METHODS: The medical records of 1599 consecutive patients who underwent either laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy between June 2005 and December 2017 were retrieved. All relevant data, including patient characteristics, biometric values before and after surgery, related medical problems, surgical history, medications, and habitus, for each patient were prospectively collected in a database. Logistic regressions were used to assess the influence of non-clinical determinants on surgical indications and complications. Multilevel linear or logistic regression was used to evaluate the influence of non-clinical determinants on long-term %TWL and the probability to achieve adequate weight loss (defined as a %TWL > 20% at 12 months). RESULTS: Analysis of the 1599 medical records revealed that most geographically isolated patients were more likely to have undergone laparoscopic Roux-en-Y gastric bypass (odds ratio: 0.97; 95% confidence interval: 0.94 to 0.99; P = 0.018) and had a greater likelihood of adequate weight loss (ß: 0.03; 95% CI: 0.01 to 0.05; P = 0.021). Conversely, socioeconomic status (measured by the European Deprivation Index) did not affect outcomes following bariatric surgery. CONCLUSION: Geographical health isolation is associated with a higher probability to achieve adequate weight loss after 1 year of follow-up, while neither health isolation nor socioeconomic deprivation is associated with post-operative mortality and morbidity. This results suggests that bariatric surgery is a safe and effective tool for weight loss despite socioeconomic deprivation.

Influence of non-clinical factors on restorative rectal cancer surgery: An analysis of four specialized population-based digestive cancer registries in France.

BACKGROUND: This study aims to measure the association between deprivation, health care accessibility and health care system with the likelihood of receiving non-restorative rectal cancer surgery (NRRCS). METHODS: All adult patients who had rectal resection for invasive adenocarcinoma diagnosed between 2007 and 2016 in four French specialised cancer registries were included. A multilevel logistic regression with random effect was used to assess the link between patient and health care structure characteristics on the probability of NRRCS. RESULTS: 2997 patients underwent rectal cancer resection in 68 health care structures: 708 (23.63%) had NRRCS. The likelihood of receiving NRCCS was associated with patients' characteristics (97%): age, sub peritoneal rectal tumors, neoadjuvant therapy, residual tumour and stage III . There was no impact of European Deprivation Index or remoteness on NRRCS. Inter-health care structure variability was modest (3%), of which 50% was explained by the high group volume of colorectal procedures and the type of health care structure which were associated with less NRRCS (p<0.01). CONCLUSION: There is an influence of operating volume and type of structure on the probability of NRRCS, but it has truly little importance in explaining differences in performances. The probability of NRRCS is mainly affected by clinical determinant.