Preoperative Weight Loss as a Predictor of Short and Midterm Postoperative Weight Loss in Patients Undergoing Bariatric Surgery.

Objective To examine if preoperative weight loss correlates to postoperative weight loss 2 and 3 years after surgery. Methods A review was conducted of bariatric surgery patients who underwent either gastric bypass or sleeve gastrectomy during 2015-2018 and had 3-year follow-up data. Demographic and outcome data were collected. A best-fit regression model for weight loss was constructed. Results Eight hundred fifty-nine patients underwent surgery during the selected period, of which 199 patients (23%) were analyzed. Eighty-two percent of patients had gastric bypass and 82% were female. Preoperative percent excess weight loss (%EWL) was not significantly associated with 2- and 3-year postoperative %EWL (p = 0.18). Patients demonstrated significant weight regain at 3 years postoperatively versus 1 year (p < 0.01). Higher preoperative weight loss was associated with lower %EWL 3 years postoperatively versus 1 year (p = 0.04). Postoperative %EWL had a significant negative association with higher preoperative weight, diabetes, baseline use of a mobility device, and sleeve gastrectomy. Conclusions In a cohort of bariatric surgery patients, there was no statistically significant association between preoperative and midterm postoperative %EWL. Postoperative %EWL was negatively associated with several patient-specific factors and increasing time since operation.