Supplementary Material for: Body Adiposity Index Is Predictive of Weight Loss after Roux-en-Y Gastric Bypass

<b><i>Background/Aims:</i></b> Roux-en-Y gastric bypass (RYGB) is one of the most effective therapies for morbid obesity, yet some patients who have taken the surgery still undergo insufficient weight loss. Visceral adiposity index (VAI), lipid accumulation product (LAP), body adiposity index (BAI), and cardiometabolic index (CMI) have been regarded as clinical indicators of adiposity phenotypes that associated closely with obesity-related metabolic diseases. However, no studies have evaluated the relationship between these indexes and weight loss after bariatric surgery. In this prospective study, we aimed to evaluate whether VAI, LAP, BAI, and CMI would predict postoperative weight loss outcomes after RYGB. <b><i>Methods:</i></b> This study included 38 men and 67 women who have undergone RYGB between January 2017 and May 2018 and recorded their %TWL (percent of total weight loss), �MIL (percent of excess body mass index loss), %EWL (percent of excess weight loss), anthropometric indices, and biochemical parameters before and 12 months after the surgery. In addition, VAI, LAP, BAI, and CMI were measured with anthropometric measures or lipid profiles using related equations and analyzed with metabolic characteristics. <b><i>Results:</i></b> Subjects with lower BAI (&lt;32.54 in men and 37.39 in women) displayed higher �MIL and %EWL 12 months after surgery. BAI was independently associated with %EWL 12 months after surgery in both men and women (both <i>p</i> &lt; 0.05). The area under the receiver operating characteristic curve for BAI was significantly higher (0.773 in men and 0.818 in women) than VAI, LAP, and CMI. <b><i>Conclusions:</i></b> BAI serves as a reliable surrogate marker of the weight loss outcome after RYGB. The predictivity of adiposity indexes in beneficial outcomes after weight loss therapies is of important referential value for the implementation and optimization of individualized and refined weight loss treatments for obese patients.

**背景与目的**：Roux-en-Y胃旁路术（Roux-en-Y gastric bypass, RYGB）是治疗病态肥胖最有效的手段之一，但部分接受该手术的患者术后体重下降仍未达到理想水平。内脏脂肪指数（Visceral adiposity index, VAI）、脂质蓄积指数（lipid accumulation product, LAP）、体脂指数（body adiposity index, BAI）及心脏代谢指数（cardiometabolic index, CMI）均被视为与肥胖相关代谢疾病密切相关的体脂表型临床评估指标。然而目前尚无研究探讨此类指标与减重代谢手术后体重变化的关联。本前瞻性研究旨在明确VAI、LAP、BAI及CMI能否预测Roux-en-Y胃旁路术后的体重下降结局。

**方法**：本研究纳入2017年1月至2018年5月间接受Roux-en-Y胃旁路术的38例男性与67例女性受试者，记录其术前及术后12个月的总体体重丢失百分比（%TWL）、超额体质量指数丢失百分比（%EMIL）、超额体重丢失百分比（%EWL）、人体测量学指标及生化参数。此外，通过人体测量数据或血脂谱结合相关公式计算VAI、LAP、BAI及CMI，并分析其与代谢特征的关联。

**结果**：体脂指数（BAI）较低的受试者（男性＜32.54，女性＜37.39）术后12个月的%EMIL及%EWL更高。在男性及女性群体中，BAI均与术后12个月的%EWL独立相关（均P<0.05）。BAI的受试者工作特征（Receiver Operating Characteristic, ROC）曲线下面积（男性0.773、女性0.818）显著高于VAI、LAP及CMI。

**结论**：BAI可作为Roux-en-Y胃旁路术后体重下降结局的可靠替代标志物。体脂指标在减重治疗获益结局中的预测价值，可为肥胖患者个体化、精细化减重方案的制定与优化提供重要参考依据。