Higher neutrophil counts and neutrophil-to-lymphocyte ratio predict prognostic outcomes in patients after non-atrial fibrillation-caused ischemic stroke

Background We aimed to determine whether higher neutrophil counts (NC) and neutrophil-to-lymphocyte ratio (NLR) were independently predictive of worse in-hospital outcome in patients after acute ischemic stroke (IS). Methods A retrospective observational study with prospective manner of IS registration. Between April 2012 and August 2014, a total number of 1731 patients with post-IS were consecutively enrolled in the study. Blood samples were drawn upon admission. Primary endpoint was in-hospital mortality. Secondary endpoint was severe stroke (≥16 NIHSS). Results The NC progressively increased from mild (NIHSS ≤ 5) to moderate (NIHSS ≥ 6 < 16) and severe (NIHSS ≥ 16) stroke (p = 0.006). NLR was independently associated with in-hospital mortality (p = 0.002). Multiple stepwise linear regression analysis showed that NC (p = 0.001) and NLR (p = 0.002) were independently predictive of higher NIHSS. Multiple stepwise logistic regression analysis showed that NC was independently associated with severe stroke (p < 0.0001). The best discriminating factor for in-hospital mortality with respect to NLR was ≥3.20 (sensitivity 62.7%, specificity 60.3%, likelihood ratio: 12.2). Patients with NLR ≥3.20 had a 2.55-fold increased risk for in-hospital mortality (OR = 1.49–4.37) compared to patients with NLR <3.20. The best discriminating factor for severe stroke (≥16 NIHSS) with respect to NC was ≥74% (sensitivity 47.1%, specificity 74.0%, likelihood ratio: 29.0). Patients with NC >74% had a 2.54-fold increased risk of severe stroke (OR = 1.82–3.54) compared to patients with NC <74%. Conclusion NLR was independently associated with in-hospital mortality and higher NC was independently predictive of severe stroke.