Differential leukocyte counts on admission predict outcomes in patients with acute ischaemic stroke treated with intravenous thrombolysis

Abstract

BACKGROUND AND PURPOSE: To determine the association of differential leukocyte counts on admission with efficacy and safety outcomes in patients with acute ischaemic stroke (AIS) treated with intravenous thrombolysis (IVT). METHODS: Consecutive patients with AIS receiving IVT were evaluated at two stroke centers. Differential leukocyte counts and neutrophil:lymphocyte ratio (NLR) were determined during the initial 12 h of admission. Efficacy outcomes were favorable functional outcome (FFO) (modified Rankin Scale scores of 0-1) and functional independence (FI) (modified Rankin Scale scores of 0-2) at 3 months, whereas safety outcomes were symptomatic intracranial hemorrhage and 3-month mortality. RESULTS: Among 657 IVT-treated patients with AIS, the mean age was 64 ± 14 years, 50% were female and median National Institutes of Health Stroke Scale score was 7 points (interquartile range, 4-13). Lower neutrophil and leukocyte counts and NLR counts were observed in patients with 3-month FFO and FI, whereas higher counts were observed in patients who died at 3 months. The best discriminative factors for 3-month FFO and FI were NLR < 2.2 (sensitivity 51.4%, specificity 63.1%) and leukocyte count <8100/μL (sensitivity 57.5%, specificity 55.1%), respectively. After adjustment for potential confounders, NLR < 2.2 was associated with higher odds of FFO [odds ratio (OR), 1.56; 95% confidence interval (CI), 1.08-2.24; P = 0.018], whereas leukocyte count <8100/μL demonstrated higher odds of 3-month FI (OR, 1.69; 95% CI, 1.11-2.57; P = 0.014) and lower odds of 3-month mortality (OR, 0.31; 95% CI, 0.16-0.60; P = 0.001). Combined neutrophil (<6800/μL) and leukocyte (<8100/μL) counts demonstrated a strong interaction for 3-month FI (OR, 1.73; 95% CI, 1.13-2.67; P interaction = 0.012). CONCLUSIONS: Differential leukocyte counts on admission were independently associated with clinical outcomes in patients with AIS treated with IVT. These inflammatory biomarkers are potential targets for adjunctive neuroprotection in this stroke subgroup.