Background. The prognostic nutritional index (PNI) has been reported to significantly correlate with poor survival and postoperative complications in patients with various diseases, but its relationship with mortality in COVID-19 patients has not been addressed. Method. A multicenter retrospective study involving patients with severe COVID-19 was conducted to investigate whether malnutrition and other clinical characteristics could be used to stratify the patients based on risk. Results. A total of 395 patients were included in our study, with 236 patients in the training cohort, 59 patients in the internal validation cohort, and 100 patients in the external validation cohort. During hospitalization, 63/236 (26.69%) and 14/59 (23.73%) patients died in the training and validation cohorts, respectively. PNI had the strongest relationships with the neutrophil-lymphocyte ratio (NLR) and lactate dehydrogenase (LDH) level but was less strongly correlated with the CURB65, APACHE II, and SOFA scores. The baseline PNI score, platelet (PLT) count, LDH level, and PaO₂/FiO₂ (P/F) ratio were independent predictors of mortality in COVID-19 patients. A nomogram incorporating these four predictors showed good calibration and discrimination in the derivation and validation cohorts. A PNI score less than 33.405 was associated with a higher risk of mortality in severe COVID-19 patients in the Cox regression analysis. Conclusion. These findings have implications for predicting the risk of mortality in COVID-19 patients at the time of admission and provide the first direct evidence that a lower PNI is related to a worse prognosis in severe COVID-19 patients.

中文翻译：

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重症 COVID-19 患者预后营养指数 (PNI) 的预测意义

背景。据报道，预后营养指数（PNI）与各种疾病患者的不良生存率和术后并发症显着相关，但它与 COVID-19 患者死亡率的关系尚未得到解决。方法。一项涉及重症 COVID-19 患者的多中心回顾性研究旨在调查营养不良和其他临床特征是否可用于根据风险对患者进行分层。结果. 我们的研究共纳入 395 名患者，其中 236 名患者在训练队列中，59 名患者在内部验证队列中，100 名患者在外部验证队列中。住院期间，训练组和验证组分别有 63/236 (26.69%) 和 14/59 (23.73%) 名患者死亡。PNI 与中性粒细胞-淋巴细胞比率 (NLR) 和乳酸脱氢酶 (LDH) 水平的相关性最强，但与 CURB65、APACHE II 和 SOFA 评分的相关性较弱。基线 PNI 评分、血小板 (PLT) 计数、LDH 水平和 PaO ₂ /FiO ₂(P/F) 比率是 COVID-19 患者死亡率的独立预测因子。包含这四个预测因子的列线图在推导和验证队列中显示出良好的校准和区分。在 Cox 回归分析中，PNI 评分低于 33.405 与重症 COVID-19 患者的死亡风险较高相关。结论。这些发现对预测 COVID-19 患者入院时的死亡风险具有重要意义，并提供了第一个直接证据，即较低的 PNI 与重症 COVID-19 患者的预后较差有关。