Red blood cell distribution width is associated with mortality after acute ischemic stroke: a cohort study and systematic review.

Abstract

Whether red blood cell distribution width (RDW) is associated with the prognosis of acute ischemic stroke is inconclusive according to recent studies. We performed a cohort study and meta-analysis to explore the association between RDW and functional outcome. Patients with ischemic stroke admitted to the Department of Neurology within 24 hours of stroke onset between January 1, 2015 to December 31, 2018 were enrolled. Blood was sampled within 24 hours after admission. We searched PubMed, Embase, Web of Science databases up to Nov 2019 to identify studies investigating the association between RDW values and prognosis following stroke. Outcomes included 3-month death and poor functional outcome [defined by modified Rankin Scale (mRS) score ≥3]. We included 1,558 patients in cohort study. RDW was independently associated with 3-month death [odds ratio (OR), 1.19; 95% confidence interval (CI), 1.03, 1.37], but not associated with 3-month poor outcome (OR 1.05, 95% CI, 0.95, 1.16), after adjustment for confounders. A dose-dependent relationship between RDW levels and 3-month death was revealed in the restricted cubic spline plot. Seven observational studies with 4,407 patients were identified for systematic review. When combining our study and previous studies, the association was significant for RDW predicting death (5 studies with 3,366 patients, OR 1.25, 95% CI, 1.15, 1.35), as well as for poor outcome (4 studies with 3,483 patients, OR 1.23, 95% CI, 1.05, 1.44). RDW was an independent predictor of 3-month functional outcome, and a trend of dose-dependent relationship between RDW and 3-month death was detected.