Evidence map›Paper›PMID 42021179›Full record

ArticleBMC neurology2026

Nonlinear threshold effect of neutrophil-to-lymphocyte ratio for predicting stroke-associated pneumonia in acute ischemic stroke: a retrospective cohort study in afebrile patients at admission.

Huimin Zhang, Weixuan Chen, Ming Yang, Haiyan Zheng, Zhaoping Wu, Tingting Duan

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Article in BMC neurology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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5 · Who and what money

Authors and funding

6 authors.

Huimin ZhangDepartment of Neurology, The First People's Hospital of LIN'AN District, Hangzhou, China.
Weixuan ChenDepartment of Neurosurgery, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, China.
Ming YangDepartment of Neurology, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, China.
Haiyan ZhengDepartment of Neurology, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, China.
Zhaoping WuDepartment of Neurology, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, China.
Tingting DuanDepartment of Neurology, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, China. qz.dtt001@wmu.edu.cn.

Funding

G-class Quzhou City Medical and Health Talents Scientific Research Startup Fund Project No. KYQD2025-03Quzhou Municipal Science and Technology Bureau Project No. 2025K035
6 · The paper itself

Abstract

backgroundStroke-associated pneumonia (SAP) is a common and serious complication after acute ischemic stroke (AIS), leading to increased morbidity, mortality, and healthcare burden. The neutrophil-to-lymphocyte ratio (NLR) has emerged as a promising biomarker of systemic inflammation, but its predictive value and potential nonlinear threshold effect for SAP remain unclear.

methodsWe conducted a retrospective cohort study involving 1,473 consecutive afebrile patients with acute ischemic stroke (AIS) who were admitted to a tertiary stroke center between January 2019 and December 2023. The neutrophil-to-lymphocyte ratio (NLR) was calculated from complete blood counts obtained at admission and log₂-transformed for statistical analysis. Stroke-associated pneumonia (SAP) was diagnosed according to modified criteria from the Centers for Disease Control and Prevention (CDC) and established consensus guidelines. The association between log₂-transformed NLR and SAP was assessed using multivariable logistic regression, adjusting for 22 potential confounders. Threshold effects were explored through piecewise regression analysis. Evaluate predictive performance using receiver operating characteristic (ROC) curve and DeLong test.

resultsAmong 1,473 patients, 339 (23.0%) developed SAP. Patients with SAP had significantly higher NLR levels (median 4.20 vs. 2.39, P < 0.001). After multivariable adjustment, each doubling of NLR was associated with a 51% increased risk of SAP (OR 1.51, 95% CI 1.28–1.79, P < 0.001). Segmented regression identified an inflection point at NLR = 1.79 (log₂-NLR = 0.84). Below this threshold, NLR showed no significant association with SAP (OR 0.42, P = 0.054), while above the threshold, the association was significant (OR 1.44, 95% CI 1.21–1.71, P < 0.001). The combination model of NLR + CRP + WBC achieved the highest discriminatory ability (AUC = 0.875). Subgroup analyses showed consistent associations across different patient characteristics (all P for interaction > 0.05).

conclusionsElevated NLR is independently associated with SAP in AIS patients, with a threshold effect at NLR = 1.79. NLR may serve as a simple and readily available biomarker for SAP risk stratification. Patients with NLR ≥ 1.79 may benefit from enhanced monitoring and preventive interventions.

Indexed as

Ischemic StrokeLymphocytesNeutrophilsPneumoniaAgedAged, 80 and overBiomarkersCohort StudiesFemaleHumansLymphocyte CountMaleMiddle AgedPredictive Value of TestsRetrospective StudiesStrokeBiomarkersAcute ischemic strokeBiomarkerInflammationNeutrophil-to-lymphocyte ratioStroke-associated pneumoniaThreshold effect

Identifiers

PMID42021179
PMCPMC13238045

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.