Peripheral blood cell count ratios as a predictor of poor functional outcome in patients with acute ischemic stroke

Acute ischemic stroke (AIS) is a leading cause of death and long-term disability worldwide. Thromboinflammation plays an important role in the pathophysiology of stroke. The peripheral blood cell count ratios (PBCCR): neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR), are global inflammatory indicators with prognostic value for the clinical outcome after stroke. We aimed to determine the relationship between NLR, PLR, or LMR and the functional outcome three months post-stroke.

A prospective, hospital-based study, including 141 participants with AIS, was conducted at a referral stroke center in North-Eastern Bulgaria. The PBCCRs were obtained during the first 24 hours after stroke onset. Stroke severity was measured using the NIHSS scale, and functional outcome was assessed with the modified Rankin Scale (mRS) at discharge and 3 months post-stroke.

We found significantly lower total lymphocyte counts, and higher NLR, PLR, and C-reactive protein in the poor-outcome group (mRS>3) three months post-stroke. A positive correlation was found between the NIHSS score and mRS score on discharge, NLR, and PLR with the worse outcome on the third month. The receiver operating characteristic (ROC) curves showed the predictability of NLR (AUC, 0.626, 95%CI: 0.524-0.724, p = 0.018), and for PLR- (AUC, 0.613, 95%CI: 0.510-0.716, p = 0.031). The optimal cutoff value for NLR was 2.68 (sensitivity 77.8% and specificity 60.4%), and for PLR - 122.6 (sensitivity 77.8% and specificity 61.5%).

Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio are simple, widely available, and cost-effective biomarkers with high prognostic value for the clinical outcome three months post-stroke.