Zhimin Chen,1,* Zongbo Shen,2,* Jing Sun,3,* Honglan Gao,1 Zhongxiang Liu,4 Hui Lu5 

1Department of Clinical Nutrition, The Yancheng Clinical College of Xuzhou Medical University, The First People’s Hospital of Yancheng, Yancheng, 224000, People’s Republic of China; 2Department of Respiratory and Critical Care Medicine, The People’s Hospital of Lincang, Lincang, 677099,People’s Republic of China; 3Department of Thoracic Surgery, The Yancheng Clinical College of Xuzhou Medical University, The First People’s Hospital of Yancheng, Yancheng, 224000, People’s Republic of China; 4Department of Respiratory and Critical Care Medicine, The Yancheng Clinical College of Xuzhou Medical University, The First People’s Hospital of Yancheng, Yancheng, 224000, People’s Republic of China; 5Nursing Department, The Yancheng Clinical College of Xuzhou Medical University, The First People’s Hospital of Yancheng, Yancheng, 224000, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Hui Lu, The Yancheng Clinical College of Xuzhou Medical University, the First People’s Hospital of Yancheng, Renminnan Road, No. 66, Yancheng, 224000, People’s Republic of China, Email 5114082@qq.com Zhongxiang Liu, Email liuzhongxiang711@163.com

Background: The neutrophil percentage-to-albumin ratio (NPAR) has emerged as a widely used inflammatory marker for predicting clinical outcomes across various diseases; however, its prognostic value in hypercapnic respiratory failure (HRF) remains uncertain. This study aimed to examine the association between NPAR and all-cause mortality in patients with HRF.
Methods: This prospective cohort study enrolled 561 HRF patients hospitalized at Yancheng First People’s Hospital between October 2020 and September 2021. The primary outcome was 24-month all-cause mortality; secondary outcomes included mortality at 3, 6, and 12 months. The association between NPAR and all-cause mortality was assessed using restricted cubic spline (RCS) modeling, multivariate Cox proportional hazards models, Kaplan-Meier survival analysis, and subgroup analyses. Discriminatory performance was evaluated using the area under the receiver operating characteristic curve (AUC).
Results: RCS modeling demonstrated a significant linear association between NPAR and all-cause mortality in HRF patients (P for overall association < 0.001). Both the Cox models and Kaplan-Meier analyses indicated that elevated NPAR levels were significantly associated with increased 3-, 6-, 12-, and 24-month all-cause mortality (all P < 0.05). Subgroup analysis further supported an independent association between NPAR and mortality. The AUC for NPAR in predicting 12-month all-cause mortality was 0.66 (95% confidence interval [CI], 0.61– 0.71), which was significantly higher than that of neutrophil percentage or albumin alone (AUC =0.62; 95% CI, 0.57– 0.67; P < 0.05).
Conclusion: Elevated NPAR is independently associated with increased all-cause mortality in patients with HRF. As a composite marker reflecting both systemic inflammation and nutritional status, NPAR may serve as a robust prognostic indicator to enhance risk stratification and guide clinical decision-making in HRF management.

Keywords: neutrophil percentage-to-albumin ratio, all-cause mortality, hypercapnic respiratory failure