Article Title

Five-Year Weight Change Trajectories in Roux-en-Y Gastric Bypass Patients

Publication Date



obesity, bariatric surgery


Background/Aims: Roux-en-Y gastric bypass (RYGB) is a popular weight-loss procedure, but not all patients experience optimal long-term outcomes. Previous studies indicate that bariatric surgery patients with similar preoperative profiles may respond differently to the same surgical intervention for severe obesity. This study’s primary aim was to identify long-term weight change trajectories in a large cohort of RYGB patients over 5 years.

Methods: This longitudinal study followed adult RYGB patients preoperatively to 5 years postoperatively. Patients were recruited from 2004 to 2014 from the bariatric surgery program of a large comprehensive rural medical center. Demographic and weight information was obtained through the electronic medical record. The study’s primary outcome, percent total body weight loss (% TBWL), was calculated using the weight at time of surgery and all weights available in the electronic medical record as part of routine clinical care through 5 years after surgery. Weight loss trajectories were then estimated using a semiparametric latent class growth modeling approach.

Results: The majority of RYGB participants (N = 3,215) were female (80%, 2,575 of 3,215); mean preoperative body mass index (BMI) was 49.4 ± 8.8 kg/m2. Four distinct weight loss trajectories were identified for the 5 years following RYGB. In our sample, 16.8% (541 of 3,215) of participants failed to maintain 20% of their initial weight loss, representing a “suboptimal” weight loss trajectory group. Two additional groups (combined 15.9%, 513 of 3,215) reached similar weight loss endpoints at 5 years (approximately 40% TBWL), with a subset of these participants following a slower but steady trajectory (7.6%, 245 of 3,215). Finally, a fourth group (67.2%, 2,161 of 3,215) reached a weight loss nadir of about 30% and maintained 25% weight loss at Year 5.

Conclusion: Weight change trajectories after RYGB are not uniform, with some patients experiencing suboptimal weight loss of less than 20% by Year 5. Greater understanding of the individual-level characteristics that distinguish patients with suboptimal weight change may help to improve patient and procedure selection.




June 28th, 2016


August 12th, 2016