The longitudinal trajectory of post-surgical % total weight loss among middle-aged women who had undergone bariatric surgery

•Weight loss outcomes differ between % excess weight loss and % total weight loss.•%TWL was highest among patients with preoperative BMI > 40 and RYGB procedure.•%TWL plateaued or decreased about 1 year after surgery among middle-aged females.

Middle-aged women are at a higher risk of being obese. We examined the trajectory of post-surgical % total weight loss (%TWL) among middle-aged female bariatric patients. We fitted sequential generalized estimating equations models to analyze a sample of women who received bariatric surgery in 1995-2012, aged 40-65 years at the time of surgery (N = 158,292) whose pre-operative body mass index (BMI) was ≥ 30 kg/m2 in the Bariatric Outcomes Longitudinal Database. The %TWL computed by 100% × (pre-surgery BMI − post-surgery BMI) / pre-surgery BMI showed different trajectories depending on type of surgery. For gastric banding, %TWL increased rapidly right after bariatric surgery and started to decrease around 1 year after surgery. For Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy, %TWL overall did not show remarkable changes from around 1 year after surgery. The highest increase in %TWL was observed in patients whose pre-operative BMI was 40 or higher and those who had undergone RYGB (ps < 0.001). Whereas the trajectories of %TWL among patients with sleeve gastrectomy and gastric banding did not differ much between different pre-operative BMI groups, the trajectories for RYGB were notably different between different pre-operative BMI groups (ps < 0.001). Middle-aged female bariatric patients are likely to achieve the highest %TWL if they receive RYGB and if their pre-operative BMI is 40 or higher. Further research is warranted to corroborate the present study's finding on the long-term effect of different types of bariatric surgery on %TWL among middle-aged women.