Long-Term Weight Loss and Comorbidity Resolution of Laparoscopic Sleeve Gastrectomy and Laparoscopic Roux-en-Y Gastric Bypass and the Impact of Preoperative Weight Loss on Overall Outcome.

BACKGROUND: The impact of preoperative weight loss on long-term weight loss outcomes and comorbidity resolution in both laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB) are poorly reported. Understanding this relationship is necessary to guide surgeons toward appropriate procedure and patient selection. The present study investigates long-term weight loss outcomes and comorbidity resolution following LSG and LRYGB and investigates the effect of preoperative variables on long-term outcomes. METHODS: All patients who underwent LSG and LRYGB (2008-2022) in a tertiary referral centre were followed up prospectively. From 2010, a 12-week intensive preoperative information course (IPIC) became standard practice to optimize preoperative weight loss. Excess weight loss outcomes (EWL≥50% and ≥70%) were compared between LSG and LRYGB using multivariate logistic regression and the effect of preoperative weight loss on weight loss and comorbidity resolution, improvement, and exacerbation were reported. RESULTS: A total of 319 patients (median age: 49 y; M:F, 75:244) were included (158 LSG: 161 LRYGB). During follow-up, 260 (81.5%) and 163 patients (51.1%) achieved EWL≥50% and ≥70%, respectively. Those with sustained EWL≥50% and EWL≥70% at the end of follow-up were more likely to have underwent a LRYGB versus a LSG (59.6% vs. 40.4%, P=0.002; 61.7% vs. 38.3%, P<0.001). IPIC and higher preoperative weight loss (HR: 2.59 to 3.72, P<0.001) increased rates of EWL≥50% and EWL70% for both procedures. Improvement or resolution of type-2 diabetes were significant (72.7%), but up to 27.3% of patients developed or suffered an exacerbation of a psychiatric illness. CONCLUSIONS: Excess weight loss outcomes are similar for LSG and LRYGB but LRYGB results in higher rates of sustained excess weight loss during long-term follow-up. Preoperative weight loss improves long-term weight loss. Comorbidity resolution is significant but rates of psychiatric illness exacerbation are high following metabolic and bariatric surgery.

Predicting Inadequate Weight Loss After Bariatric Surgery: Derivation and Validation of a Four Factor Model.

INTRODUCTION: Weight loss following bariatric surgery is variable and predicting inadequate weight loss is required to help select patients for bariatric surgery. The aim of the present study was to determine variables associated with inadequate weight loss and to derive and validate a predictive model. METHODS: All patients who underwent laparoscopic sleeve gastrectomy and Roux-en-Y gastrectomy (2008-2022) in a tertiary referral centre were followed up prospectively. Inadequate weight loss was defined as excess weight loss (EWL) < 50% by 24 months. A top-down approach was performed using multivariate logistic regression and then internally validated using bootstrapping. Patients were categorised into risk groups. RESULTS: A total of 280 patients (median age, 49 years; M:F, 69:211) were included (146 LSG; 134 LRYGB). At 24 months, the median total weight loss was 30.9% and 80.0% achieved EWL ≥ 50% by 24 months. Variables associated with inadequate weight loss were T2DM (OR 2.42; p = 0.042), age 51-60 (OR 1.93, p = 0.006), age > 60 (OR 4.93, p < 0.001), starting BMI > 50 kg/m² (OR 1.93, p = 0.037) and pre-operative weight loss (OR 3.51; p = 0.036). The validation C-index was 0.75 (slope = 0.89). Low, medium and high-risk groups had a 4.9%, 16.7% and 44.6% risk of inadequate weight loss, respectively. CONCLUSIONS: Inadequate weight loss can be predicted using a four factor model which could help patients and clinicians in decision-making for bariatric surgery.