Supplementary Material for: Effect of Preoperative Geriatric Nutritional Risk Index on Prognosis in Patients after Surgery for Lower Gastrointestinal Perforation

Introduction: Geriatric Nutritional Risk Index (GNRI) is a reliable index derived from serum al-bumin levels, height, and weight. Although various prognostic factors have been studied, the effect of preoperative nutritional status on surgical outcomes remains unexplored. This study aimed to evaluate the efficacy of the GNRI in predicting postoperative outcomes of lower gastro-intestinal perforation. Methods: Eighty patients treated at our institution between January 2016 and December 2022 were retrospectively analyzed. This study primarily focused on the correlation between pre-operative GNRI and two key outcomes: postoperative hospital stay duration and 1-year mortality rate. Results: Our findings revealed a significant association between low GNRI scores and increased 1-year mortality (Odd ratio 4.0, 95% confidence interval [CI] 1.1–16, p=0.025). Kaplan–Meier analysis and log-rank test showed that patients in the low GNRI group had markedly poorer overall survival rates than those in the high GNRI group (12-month survival rate 0.88 [95%CI: 0.75–0.95] vs. 0.65 [95%CI: 0.47–0.78]; p=0.018). Additionally, both univariate and multivariate analyses indicated that lower GNRI scores were associated with prolonged hospital stays. Conclusion: We showed that a low GNRI score was associated with high mortality and pro-longed hospital stay after emergency surgery for lower gastrointestinal perforation.引言：老年营养风险指数（Geriatric Nutritional Risk Index，GNRI）是一种基于血清白蛋白水平、身高与体重推导得出的可靠评估指标。尽管学界已对多种预后因素展开研究，但术前营养状态对手术结局的影响仍未得到充分探索。本研究旨在评估GNRI在预测下消化道穿孔术后结局中的应用价值。方法：本研究回顾性分析了2016年1月至2022年12月于本医疗机构收治的80例患者，主要探讨术前GNRI与两项核心结局指标的相关性：术后住院时长与1年死亡率。结果：本研究结果显示，低GNRI评分与1年死亡率升高存在显著相关性（优势比为4.0，95%置信区间（confidence interval，CI）为1.1–16，p=0.025）。Kaplan–Meier分析与对数秩检验（log-rank test）结果表明，低GNRI组患者的总体生存率显著低于高GNRI组（12个月生存率分别为0.88 [95%CI: 0.75–0.95]与0.65 [95%CI: 0.47–0.78]；p=0.018）。此外，单因素与多因素分析均显示，较低的GNRI评分与住院时长延长存在关联。结论：本研究证实，下消化道穿孔急诊术后患者若GNRI评分较低，则其死亡率更高且住院时长更长。