Red Blood Cell Distribution Width is Associated with Poor Clinical Outcome After Subarachnoid Hemorrhage: A Pilot Study

The red cell distribution width (RDW) is a biomarker strongly associated with poor outcome in inflammatory and thrombotic diseases. Subarachnoid hemorrhage (SAH) is both an inflammatory and thrombotic state in which many biomarkers have been studied. In this exploratory pilot study, we sought to determine whether RDW predicts poor outcome in patients with SAH. Patients with moderate-to-severe SAH were prospectively enrolled in an observational study of biomarkers and outcome. CBC, ESR, high sensitivity CRP, D-dimer, and fibrinogen were obtained on post-bleed days (PBD) 1, 3, 5, 7, and 10. Poor outcome was defined as a modified Rankin score of 3-6 at 90-days. Of 40 patients, 5 (12.5 %) died and 19 (47.5 %) had a poor outcome. RDW (p = 0.046) when measured serially over the study period, was significantly higher among patients with poor outcome. Maximum RDW (OR 2.3 95 % CI 1.2-3.6; p = 0.014) and maximum WBC count (OR 1.29 95 % CI 1.04-1.60; p = 0.018) were associated with poor outcome. Stepwise addition of maximum ESR, CRP, D-dimer, and fibrinogen yielded a model with RDW (OR 2.54 95 % CI 1.21-5.35; p = 0.014) and fibrinogen (OR 1.01 95 % CI 1.002-1.01; p = 0.004) predicting outcome. With addition of age and Hunt and Hess grade, RDW, fibrinogen, and high-grade status remained significantly associated with poor outcome. Use of PBD1 RDW in lieu of maximum RDW, resulted in a similar model. An elevated RDW is associated with poor outcome in SAH patients. RDW may be a useful predictor of outcomes after SAH.