Abstract 12461: Change in Red Cell Distribution Width (RDW) and Initial RDW During Hospitalization are Associated With Length of Hospital Stay and 30-Day Outcomes
Background: Higher red cell distribution width (RDW) is an independent predictor of greater morbidity and mortality in the general population and in myocardial infarction, coronary disease, heart failure (HF), and other patient sets. We aimed to study the predictive ability of RDW and change in RDW (ΔRDW) for length of stay (LOS) and 30-day outcomes for HF exacerbations.
Methods: Electronic query of Intermountain Healthcare medical records identified patients (N=6,414) with a primary diagnosis of HF who were discharged in 2004-2013, had RDW measured within 24 hours after admission, and had RDW tested at least once more during the same hospitalization. ΔRDW was calculated as the last RDW within 24 hours prior to discharge minus the first RDW. All patients were aged 65 years or older and were discharged alive and not to hospice.
Results: Average age was 78.9±7.8 years and 50.2% were female. Median LOS by ΔRDW quartiles was Q1: 4.1, Q2: 3.4, Q3: 3.6, and Q4: 4.7 days (p-trend<0.001), and by initial RDW quartiles was Q1: 3.0, Q2: 3.1, Q3: 3.7, and Q4: 4.0 days (p-trend<0.001). Both initial RDW (16.8±2.8% vs. 16.3±2.7%, p<0.001) and ΔRDW (0.21±1.09% vs. 0.14±1.04%, p=0.039) predicted 30-day readmission vs. no readmit. For 30-day decedents vs. survivors, initial RDW was 17.3±3.0% vs. 16.3±2.6% (p<0.001), while ΔRDW was +0.20±1.14% vs. +0.14±1.04% (p=0.15). In Cox regression for 30-day mortality, adjusting for 58 other variables and accounting for initial RDW (HR=1.09 per +1%, 95% CI=1.07, 1.12, p<0.001), ΔRDW had HR=1.09 per +1% (CI=1.03, 1.16, p=0.004). For mortality with RDW≤median/ΔRDW≤0 as referent, RDW>median/ΔRDW≤0 had HR=1.67 (p<0.001), RDW≤median/ΔRDW>0 had HR=1.40 (p=0.016), and RDW>median/ΔRDW>0 had HR=2.02 (p<0.001), with p-interaction=0.47. Initial RDW (r=0.157, p<0.001) but not ΔRDW (r=0.014, p=0.25) mildly correlated with initial B-type natriuretic peptide.
Conclusions: Greater ΔRDW and first RDW during HF hospitalization were associated with 30-day mortality, longer LOS, and 30-day all-cause readmission. This suggests that both RDW changes and initial RDW during hospitalization may identify patient response to care, which could aid in personalizing prognosis and treatment. Further research is needed regarding the predictors of ΔRDW.
Author Disclosures: J.B. Muhlestein: None. D.L. Lappé: None. J.L. Anderson: None. J.B. Muhlestein: None. H.T. May: None. S.T. Bennett: None. T.L. Bair: None. B.D. Horne: None.
- © 2014 by American Heart Association, Inc.