Background Delirium is an underdiagnosed and possibly preventable complication in acute stroke and is linked to poor outcome. Neutrophil-to-lymphocyte ratio (NLR), a marker of systemic inflammation, is also associated with poor outcome after acute ischemic stroke. Aim To determine whether NLR is a predictor of post-stroke delirium (PSD). Methods We reviewed the UZ Brussel stroke database and included 514 patients with acute ischemic stroke within 24 hours from stroke onset between February 2009 and December 2014. The presence of delirium was evaluated by two raters based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria, using a retrospective chart review method. When no consensus was reached, a third evaluator was consulted. Patients were divided into two groups: those who developed delirium within the first week after stroke onset (n = 201; 39%) and those who did not (n = 313; 61%). Receiver operating characteristics (ROC) and multiple logistic regression analysis (MLRA) were used to identify predictors of PSD. Results MLRA showed that NLR (odds ratio (OR) 1.14; 95% confidence interval (CI) 1.04–1.26), age (OR 1.05; 95% CI 1.03–1.07), National Institutes of Health Stroke Scale (NIHSS; OR 1.14; 95% CI 1.10–1.18), premorbid modified Rankin Scale (mRS) (OR 1.35; 95% CI 1.05–1.74) and premorbid cognitive dysfunction (OR 3.16; 95% CI 1.26–7.92) predicted PSD. ROC curve of a prediction model including NLR, age, NIHSS and premorbid cognitive dysfunction showed an area under the curve of 0.84 (95% CI = 0.81–0.88). Conclusions Besides age, stroke severity, premorbid mRS and cognitive impairment, NLR is a predictor of PSD, even independent of the development of pneumonia or urinary tract infection.

Background: A high Neutrophil-to-Lymphocyte ratio (NLR) in patients with acute ischemic stroke (AIS) has been associated with post-stroke infections, but it's role as an early predictive biomarker for post-stroke pneumonia (PSP) and urinary tract infection (UTI) is not clear.Aim: To investigate the usefulness of NLR obtained within 24 h after AIS for predicting PSP and UTI in the first week.Methods: Clinical and laboratory data were retrieved from the University Hospital Brussels stroke database/electronic record system. Patients were divided into those who developed PSP or UTI within the first week after stroke onset and those who didn't. Receiver operating characteristics (ROC) curves and logistic regression analysis were used to identify independent predictors.Results: Five hundred and fourteen patients were included, of which 15.4% (n = 79) developed PSP and 22% (n = 115) UTI. In univariate analysis, NLR was significantly higher in patients who developed PSP (4.1 vs. 2.8, p < 0.001) but not in those who developed UTI (3.3 vs. 2.9, p = 0.074). Multiple logistic regression analysis for PSP showed that NLR, male gender, dysphagia, and stroke severity measured by the National Institutes of Health Stroke Scale (NIHSS), were independent predictors of PSP. For NLR alone, the area under the curve (AUC) in the ROC curve was 0.66 (95% CI = 0.59–0.73). When combining NLR ≥ 4.7 with age >75 years, male gender, NIHSS > 7, and dysphagia, the AUC increased to 0.84 (95% CI = 0.79–0.89).Conclusion: The NLR within 24 h after AIS appears to have no predictive value for post-stroke UTI, and is only a weak predictor for identifying patients at high risk for PSP. Its predictive value for PSP appears to be much stronger when incorporated in a prediction model including age, gender, NIHSS score, and dysphagia.