Analysis of the Variability in Different Criteria to Define the Success of Bariatric Surgery: Retrospective Study 5-Year Follow-Up after Sleeve Gastrectomy and Roux-en-Y Gastric Bypass

(1) Background: The current criteria for defining good or bad responders to bariatric surgery based on the percentage of weight loss do not properly reflect the therapeutic impact of the main bariatric techniques. At present there is an urgent need to fill this gap and provide scientific evidence that better define the success or failure of bariatric surgery in the long term. (2) Methods: This is a retrospective database study of a prospective cohort with 5-year follow-up. We established the success or failure of bariatric surgery in terms of weight loss according to a selected criterion: (1) Halverson and Koehler; (2) Reinhold modified by Christou; (3) Biron; (4) TWL > 20%; (5) percentage of changeable weight (AWL > 35%). We analyzed sensitivity and specificity for successful weight loss. (3) Results: 223 (38.7%) patients underwent sleeve gastrectomy (LSG) and 353 (61.2%) underwent laparoscopic Roux-en-Y gastric bypass (LRYGBP). The success rates at 5 years are: EWL > 50% 464 (80%), Reinhold 436 (75.6%), Biron 530 (92%), TWL > 20% 493 (85.5%), AWL < 35% 419 (72.7); ≥50%EWL and alterable weight loss AWL > 35 were the most adequate criteria as their specificities and sensibility were far above >80%. (4) Conclusions: The present study shows how the different definitions of success or failure are inconsistent in relation to the outcomes of BS. However, there are some criteria that associate statistically significant differences for the resolution of comorbidities and show the highest sensitivity and specificity rates.