重症监护室中再喂养综合征患者预后营养指数与全因死亡率的关联——基于MIMIC-IV数据库的回顾性研究

Association between Prognostic Nutritional Index and All-Cause Mortality among Refeeding Syndrome Patients in the Intensive Care Unit—A Retrospective Study Based on MIMIC-IV Database

摘要: 1) 背景：再喂养综合征(Refeeding Syndrome, RFS)是一种潜在的致命性营养代谢紊乱，常与不良预后相关。预后营养指数(Prognostic Nutritional Index, PNI)作为一项综合血清白蛋白水平和淋巴细胞计数的复合指标，能够反映机体的营养和免疫状态，并在多种疾病中显示出良好的预后价值。然而，PNI对RFS患者的预后意义尚不明确。本研究旨在探讨PNI与重症监护室(Intensive Care Unit, ICU)中RFS患者全因死亡率之间的关联。2) 方法：本研究利用MIMIC-IV数据库进行了一项回顾性队列研究，目标人群为成年RFS患者。根据PNI的三分位数将患者分为低、中、高三组，采用Kaplan-Meier生存曲线、Cox比例风险模型、限制性立方样条(RCS)模型，分析患者PNI与30天和90天全因死亡率之间的关联。通过亚组分析和交互作用，进一步评估PNI对不同人群预后的影响。3) 结果：共纳入269例RFS患者，30天和90天全因死亡率分别为30.7%和38.2%。生存分析表明，低PNI组的患者生存率也较低。多因素Cox回归模型显示，在调整协变量后，较高的PNI与显著降低的死亡风险独立相关(中PNI组：30天HR 0.46，95% CI 0.26~0.83，P = 0.010；90天HR 0.50，95% CI：0.31~0.81，P = 0.004；高PNI组：90天HR 0.58，95% CI: 0.37~0.92，P = 0.021)，限制性立方样条模型揭示了PNI与死亡率之间的L形关系。亚组分析表明，各亚组内效应方向与总体研究结果一致，进一步证实了PNI对RFS患者预后预测价值的稳健性。4) 结论：预后营养指数是再喂养综合征患者短期死亡率的有效预测指标，是识别预后不良患者的潜在工具。

Abstract: 1) Background: Refeeding syndrome (RFS) is a potentially life-threatening metabolic disorder associated with poor clinical outcomes. The Prognostic Nutritional Index (PNI), a composite biomarker calculated from serum albumin and total lymphocyte count, reflects nutritional and immune status. While the PNI has established prognostic value across various diseases, its utility in predicting outcomes in patients with RFS remains undefined. Therefore, this study aimed to investigate the association between PNI and all-cause mortality in critically ill patients with RFS. 2) Methods: This retrospective cohort study utilized the MIMIC-IV database and included adult patients with RFS. These patients were then stratified into low, medium, and high PNI groups based on tertiles for comparative analysis. Kaplan-Meier survival curves, multivariate Cox proportional hazards models, and restricted cubic spline (RCS) models were employed to analyze the association between PNI and 30-day and 90-day all-cause mortality. Furthermore, subgroup analyses and interaction texts were performed to further evaluate the impact of PNI on prognosis across different populations. 3) Results: A total of 269 patients with RFS were included in the final analysis. The all-cause mortality rates at 30 and 90 days were 30.7% and 38.2%, respectively. Kaplan-Meier analysis showed that patients in the low PNI group had the poorest survival. In the multivariable Cox regression model, after adjustment for potential confounders, higher PNI remained an independent predictor of reduced mortality (Medium PNI group:30-day HR 0.46, 95% CI 0.26~0.83, P = 0.010; 90-day HR 0.50, 95% CI: 0.31~0.81, P = 0.004; High PNI group: 90-day HR 0.58, 95% CI: 0.37~0.92, P = 0.021). This non-linear association was further characterized by a L-shaped relationship between PNI and mortality risk using restricted cubic spline analysis. Moreover, subgroup analyses revealed consistent effect directions across all subgroups, indicating the robustness of PNI as a prognostic marker in RFS patients. 4) Conclusion: The Prognostic Nutritional Index effectively predicts short-term mortality, supporting its use as a risk-stratification tool in refeeding syndrome.