Waist-to-Height Ratio as a Predictor Complementary to BMI for Postoperative Pancreatic Fistula After Pancreatoduodenectomy for Periampullary Tumors.

Abstract

Obesity is a known risk factor for postoperative pancreatic fistula (POPF) after pancreatoduodenectomy (PD). However, the body mass index (BMI) does not adequately reflect fat distribution or distinguish between fat and muscle mass. The waist-to-height ratio (WHR), an indicator of central adiposity, may provide complementary value to BMI in assessing the risk of POPF. This study retrospectively analyzed 523 patients who underwent PD, excluding those with pancreatic cancer. Preoperative computed tomography (CT) was used to evaluate BMI, WHR, and visceral/subcutaneous fat area. The study defined POPF as International Study Group on Pancreatic Surgery (ISGPS) grade B or C. The distributions of BMI and WHR were examined, and the predictive performance of POPF was evaluated. The overall incidence of POPF was 52.2%. Although only 16.8% of the patients met the BMI-based definition of obesity (BMI ≥ 25 kg/m²), 57.4% exhibited central adiposity (WHR ≥ 0.5). Of the entire cohort, 40.7% had a "normal" BMI but an elevated WHR. The optimal cutoff values determined by Youden's index were 21.96 kg/m² for BMI and 0.51 for WHR, both of which demonstrated good predictive accuracy (area under the receiver operating characteristic (ROC) curve, 0.797 and 0.779, respectively). A multivariate analysis showed that both BMI-defined obesity (odds ratio [OR], 6.96; p < 0.001) and WHR-defined central adiposity (OR 6.75; p < 0.001) were independently associated with POPF. The WHR is a simple and useful marker that complements BMI in preoperative assessment of the risk of POPF. It can identify patients with central adiposity who may not be classified as obese by BMI alone, thus enhancing preoperative risk stratification.