Monocyte-to-lymphocyte (MLR) and neutrophil-to-monocyte ratios (NMR) as markers of stroke and clinical characteristics

Abstract

Background: Stroke is a major global public health challenge due to its high rates of mortality, morbidity, and long-term disability, resulting in a substantial impact on patients' quality of life. Inflammatory biomarkers, such as the monocyte-to-lymphocyte ratio (MLR) and neutrophil-to-monocyte ratio (NMR), have been associated with several cardiovascular conditions, and might be correlated with ischemic stroke. Objective: Evaluate MLR and NMR values in the first 24 and 72 hours after the onset of ischemic stroke, compare the values with healthy individuals, and investigate their associations with stroke-related clinical features. Methods: This retrospective study was based on the medical records of patients aged ≥18 years who experienced an ischemic stroke between 2017 and 2025. Clinical data included ischemic stroke subtype according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification, stroke severity assessed by the National Institutes of Health Stroke Scale (NIHSS), and the presence of vascular risk factors. Based on peripheral blood cell counts, the monocyte-to-lymphocyte ratio (MLR; monocytes/mm³ divided by lymphocytes/mm³) and neutrophil-to-monocyte ratio (NMR; neutrophils/mm³ divided by monocytes/mm³) were calculated. Results: A total of 194 patients with ischemic stroke and 24 healthy controls were included. Healthy individuals exhibited lower MLR and higher NMR values than stroke patients. Greater neurological severity, as measured by the NIHSS, was associated with higher MLR values at both 24 and 72 hours after stroke onset. Among the etiological subtypes analyzed, small-vessel stroke presented significantly lower MLR values compared with cardioembolic and large-artery atherosclerotic stroke. Intravenous thrombolysis was associated with higher MLR values within the first 24 hours after stroke onset. No significant associations were observed between MLR or NMR values and stroke topography or traditional vascular risk factors. Conclusion: Patients with ischemic stroke showed higher MLR and lower NMR values than healthy controls. Elevated MLR was associated with greater neurological impairment in the acute phase of ischemic stroke, while lower MLR values in small-vessel stroke suggest distinct inflammatory profiles among stroke subtypes. These findings support the potential utility of MLR as an accessible and cost-effective inflammatory biomarker for assessing stroke severity.