Early postoperative weight loss predicts nadir weight and weight regain after laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass

Background Weight regain (WR) post bariatric surgery affects almost 20% of patients. It has been theorized that a complex interplay between physiologic adaptations and epigenetic mechanisms promotes WR in obesity, however, reliable predictors have not been identified. Our study examines the relationship between early postoperative weight loss (WL), nadir weight (NW), and WR following laparoscopic Roux-en-Y gastric bypass (LRYGB) and sleeve gastrectomy (LSG). Methods A retrospective review of prospectively collected data was conducted for LRYGB or LSG patients from 2012 to 2016. Demographics, preoperative BMI, procedure type, and postoperative weight at 6, 12, 24, 36, and 48 months were recorded. WR was defined as > 20% increase from NW. Univariate and multivariate linear and logistic regression models were used to determine the association between early postoperative WL with NW and WR at 4 years. Results Thousand twenty-six adults were included (76.8% female, mean age 44.9 ± 11.9 years, preoperative BMI 46.1 ± 8); 74.6% had LRYGB and 25.3% had LSG. Multivariable linear regression models showed that greater WL was associated with lower NW at 6 months (Coef − 2.16; 95% CI − 2.51, − 1.81), 1 year (Coef − 2.33; 95% CI − 2.58, − 2.08), 2 years (Coef − 2.04; 95% CI − 2.25, − 1.83), 3 years (Coef − 1.95; 95% CI − 2.14, − 1.76), and 4 years (Coef − 1.89; 95% CI − 2.10, − 1.68), p ≤ 0.001. WR was independently associated with increased WL between 6 months and 1 year (Coef 1.59; 95% CI 1.05,2.14; p ≤ 0.001) and at 1 year (Coef 1.24; 95% CI 0.84,1.63; p ≤ 0.001) postoperatively. The multivariable logistic regression model showed significantly increased risk of WR at 4 years for patients with greater WL at 6 months (OR 1.20, 95% CI 1.08,1.33; p = 0.001) and 1 year (OR 1.14; 95% CI 1.06,1.23; p ≤ 0.001). Conclusion Our findings demonstrate that higher WL at 6 and 12 months post bariatric surgery may be risk factors for WR at 4 years. Surgeons may need to follow patients with high early weight loss more closely and provide additional treatment options to maximize their long-term success.