Prediction of excess weight loss after laparoscopic Roux-en-Y gastric bypass: data from an artificial neural network

Abstract

Introduction Laparoscopic Roux-en-Y Gastric Bypass (LRYGB) has become the gold standard for surgical weight loss. The success of LRYGB may be measured by excess body-mass index loss (%EBMIL) over 25 kg/m2, which is partially determined by multiple patient factors. In this study, artificial neural network (ANN) modeling was used to derive a reasonable estimate of expected postoperative weight loss using only known preoperative patient variables. Additionally, ANN modeling allowed for the discriminant prediction of achievement of benchmark 50% EBMIL at one year postoperatively. Methods Six-hundred and forty-seven LRYGB included patients were retrospectively reviewed for preoperative factors independently associated with EBMIL at 180 and 365 days postoperatively (EBMIL180 and EBMIL365, respectively). Previously validated factors were selectively analyzed, including age; race; gender; preoperative BMI (BMI0); hemoglobin; and diagnoses of hypertension (HTN), diabetes mellitus (DM), and depression or anxiety disorder. Variables significant upon multivariate analysis (P<.05) were modeled by “traditional” multiple linear regression and an ANN, to predict %EBMIL180 and %EBMIL365. Results The mean EBMIL180 and EBMIL365 were 56.4%±16.5% and 73.5%±21.5%, corresponding to total body weight losses of 25.7%±5.9% and 33.6%±8.0%, respectively. Upon multivariate analysis, independent factors associated with EBMIL180 included black race (B=−6.3%, P<.001), BMI0 (B=−1.1%/unit BMI, P<.001) and DM (B=−3.2%, P<.004). For EBMIL365, independently associated factors were female gender (B=6.4%, P<.001), black race (B=−6.7%, P<.001), BMI0 (B=−1.2%/unit BMI, P<.001), HTN (B=−3.7%, P=.03) and DM (B=−6.0%, P<.001). Pearson r2 values for the multiple linear regression and ANN models were .38 (EBMIL180) and .35 (EBMIL365), and .42 (EBMIL180) and .38 (EBMIL365), respectively. ANN-prediction of benchmark 50% EBMIL at 365 days generated an area under the curve of 0.78±0.03 in the training set (n=518), and 0.83±0.04 (n=129) in the validation set. Conclusions Available at https://redcap.vanderbilt.edu/surveys/?s=3HCR43AKXR, this, or other ANN models may be used to provide an optimized estimate of postoperative EBMIL following LRYGB.

The Use of Predictive Markers for the Development of a Model to Predict Lowest Quartile Weight Loss following Roux-en-Y Gastric Bypass.

“…The literature has been unclear on this issue and we hope our study ultimately helps determine whether or not if affects weight loss after RYGB. (10,27) We also did not find GERD to be a factor which agrees with previously published literature for the RYGB (28). Sleep apnea has not previously been shown to effect weight loss in studies which agrees with our results as sleep apnea was not found to be a significant factor.…”

“…Literature is split on whether hypertension effects weight loss however in our study we found that it had no effect on eventual weight loss (10,29,30).…”

“…In 2015 Wise et al used a newer innovation in artificial neural networks to make a workable preoperative prediction of weight loss model (10). Their results were remarkable with their accuracy and prediction power.…”

Red cell distribution width is a novel biomarker that predicts excess body-mass index loss 1 year after laparoscopic Roux-en-Y gastric bypass

“…Initial BMI has been the pre-operative factor most consistently predictive, however, comorbidities such as hypertension, diabetes and psychiatric disorders, as well as race, gender and the presence of pre-operative weight loss have all been reported as well. 3, 6, 26–28 In this study, 547 LRYGB patients over a ten year period from a single institution were retrospectively reviewed to test our hypothesis that RDW may predict EBMIL. We aimed to determine the association between RDW and EBMIL, however, there was a need to control for the baseline demographics of gender, age and BMI 0 such that any significance in our suspected correlation could have wide applicability and validity.…”

“…3–5 Of the commonly performed bariatric operations, the Roux-en-Y gastric bypass is perhaps the most effective, consistently leading to sustained weight loss in the compliant patient. 6 It is typically performed laparoscopically, with few complications and rapid recovery. In anticipation of this operation, routine pre-operative blood work is often conducted to assess the patient’s iron stores, as post-operative anemia is a common, recognized sequela.…”