Jun Wan,1,* Yuyang Liu,1,* Xiang Yuan,2 Shijie Fan,1 Yangchun Xiao,3 Fang Fang,2 Yu Zhang3 

1Center for Evidence-Based Medicine, Clinical Medical College and Affiliated Hospital of Chengdu University, Chengdu, Sichuan, People’s Republic of China; 2Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China; 3Department of Neurosurgery, Clinical Medical College and Affiliated Hospital of Chengdu University, Chengdu, Sichuan, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Yu Zhang, Department of Neurosurgery, Clinical Medical College and Affiliated Hospital of Chengdu University, Chengdu, Sichuan, People’s Republic of China, Tel +8618113034616, Email zhangyu1057@cdu.edu.cn

Background and Aim: Pneumonia is a significant complication that negatively impacts outcomes in patients with intracerebral hemorrhage (ICH). Identifying reliable biomarkers for predicting such infections is crucial for timely intervention and improving patient management. This study aims to evaluate the predictive value of neutrophil-to-albumin Ratio (NAR)for pneumonia in patients undergoing surgical intervention for ICH.
Methods: This was a retrospective multicenter cohort study conducted at four tertiary hospitals. A total of 8016 patients diagnosed with spontaneous intracerebral hemorrhage (ICH) between were included. The neutrophil-to-albumin ratio (NAR) was calculated within 24 hours of admission. Logistic regression models, receiver operating characteristic (ROC) curves, and reclassification metrics (C-index, IDI, cNRI) were used to evaluate the association between NAR and the risk of pneumonia. The primary outcome was pneumonia.
Results: A total of 8016 ICH patients were included in this study. Among them, 3921 patients (48.9%) had pneumonia. There was an association between NAR levels and pneumonia (OR = 1.81, 95% CI: 1.69– 1.94, p < 0.001). After adjustment, the results remained significant (adjusted OR = 1.62, 95% CI: 1.51– 1.75, p < 0.001). Compared to patients in the Low Group (NAR ≤ 0.21), those in the High Group (NAR > 0.21) had a higher long-term mortality risk (OR = 2.95, 95% CI: 2.68– 3.24, p < 0.001; adjusted OR = 1.99, 95% CI: 1.79– 2.21, p < 0.001). Additionally, the predictive performance of NAR for pneumonia was also significant (area under the ROC curve [95% CI] 0.663 [0.651– 0.675]; p < 0.001).
Conclusion: Higher NAR is independently associated with pneumonia in patients with ICH. The early prediction of pneumonia using the simple biomarker NAR is feasible.

Keywords: intracerebral hemorrhage, neutrophil-to-albumin ratio, inflammation, pneumonia