Red cell distribution width: a novel predictive biomarker for stroke risk after transient ischaemic attack

OBJECTIVE: Predicting the prognosis of transient ischaemic attack (TIA) is difficult for many frontline clinicians. The purpose of this study was to determine whether subsequent stroke in TIA patients can be predicted via red blood cell distribution width (RDW). MATERIAL AND METHODS: A total of 360 consecutive patients with new-onset TIA in our stroke centre, were enrolled over the period studied. The patients were divided into three groups: 103 TIA patients, 206 ischaemic stroke (IS) patients and 51 patients with haemorrhagic stroke (HS) within 7 days after TIA. Complete blood count, biochemical parameters and brain imaging were performed on all patients. RESULTS: The mean RDW values of patients with IS and HS after TIA were significantly higher than patients with TIA (13.35 ± 1.59 vs 12.84 ± 1.19, 13.32 ± 1.08 vs 12.84 ± 1.19, respectively, all p ≤ .001). In a multivariate model, RDW was independently associated with stroke after TIA (IS: odds ratio (OR) = 2.52, 95% confidence interval (CI) = 1.46–3.35, p = .002; HS: OR = 1.511, 95% CI = 1.101–2.074, p = .011). Compared to ABCD(2) scores, the diagnostic power of RDW in the differentiation of patients with IS after TIA was better (area under curve (AUC): 0.731 vs 0.613, p = .015). When an RDW cut-off value of 13.95% was accepted for differentiating patients with IS from TIA, the sensitivity and specificity were 73.7% and 74.3%, respectively. However, the AUC for the ability of the RDW to predict HS was 0.653 (95% CI = 0.589–0.716; p < .001). CONCLUSIONS: KEY MESSAGES: The most important result of our study is to show that (1) the higher RDW, the earlier the stroke onset and (2) RDW ≥13.95% has a 2.52-fold risk of ischaemic stroke in TIA patients, and RDW ≥12.85% has a 1.51-fold risk of haemorrhagic stroke. As an economic and accessible hematological marker, baseline RDW may serve as a useful biomarker for risk stratification in TIA patients.