Neutrophil-to-Lymphocyte Ratio as a Complementary Marker for Stroke-Associated Pneumonia Risk in Acute Ischemic Stroke.

BACKGROUND

One of the most common nonneurological complications after stroke is stroke-associated pneumonia (SAP), which significantly increases morbidity and mortality. Early identification of factors associated with SAP is essential, with the neutrophil-to-lymphocyte ratio (NLR) emerging as a practical and accessible systemic inflammatory biomarker for clinical screening. This study is aimed at determining the incidence of SAP and analyzing the biological and mechanical factors influencing its occurrence in patients with acute ischemic stroke.

METHOD: This retrospective cohort study included consecutive patients with acute ischemic stroke whose data were extracted from medical record reviews, including admission NLR. Bivariate analyses were performed to identify factors associated with SAP, followed by multivariable logistic regression to determine independent predictors. The diagnostic performance of NLR was evaluated using receiver operating characteristic (ROC) curve analysis.

RESULTS

The incidence of SAP among 615 acute ischemic stroke patients was 19.7%. Multivariable logistic regression identified NLR > 5.21, dysphagia, NIHSS > 8, age > 60 years, and nutritional risk as independently associated with SAP. NLR > 5.21 had the largest adjusted odds ratio (aOR 11.43, 95% CI 5.74-18.93). In ROC analysis, NLR demonstrated good discrimination (AUC 0.78), although NIHSS showed higher discrimination (AUC 0.84).

CONCLUSIONS

NLR > 5.21 was independently associated with SAP and demonstrated good discriminatory performance. However, NIHSS showed superior discrimination, indicating that NLR should be considered as a complementary biomarker rather than a standalone predictor.