Centile Charts for Monitoring of Weight Loss Trajectories After Bariatric Surgery in Asian Patients.

Following bariatric surgery, accurate charting of weight loss and regain is crucial. Various preoperative factors affect postoperative weight loss, including age, sex, ethnicity, and surgical type. These are not considered by current weight loss metrics, limiting comparison of weight loss outcomes between patients or centers and across time. Patients (n=1022) who underwent sleeve gastrectomy (n=809) and gastric bypass (n=213) from 2008 to 2020 in a single center were reviewed. Weight loss outcomes (% total weight loss) were measured for 60 months postoperatively. Longitudinal centile lines were plotted using the post-estimation predictions of quantile regression models, adjusted for type of procedure, sex, ethnicity, and baseline BMI. Median regression showed that %TWL was 1.0% greater among males than females (β = +1.1, 95% CI: +0.6 to +1.7, P = <0.0001). Participants who underwent SG had less %TWL compared to GB (β = -1.3, 95% CI: -1.9 to -0.8, P < 0.0001). There was a trend towards less %TWL among the Indian and Malay participants compared to Chinese. Age and diabetes were not significant predictors. Reference centile charts were produced for the overall cohort, as well as specific charts adjusted for type of bariatric procedure, sex, ethnicity, and baseline BMI. Centile charts provide a clinically relevant method for monitoring of weight trajectories postoperatively and aid in realistic and personalised goal setting, and the early identification of “poor responders”. This is the first study to present post-bariatric surgery centile charts for an Asian cohort.