Abstract
BACKGROUND: Single red cell distribution width (RDW) assessment is a consistent prognostic marker of poor outcomes in heart failure as well as in other patient cohorts. The objective of this study was to determine the prognostic value of sequential RDW assessment in ambulatory patients with chronic heart failure. METHODS AND RESULTS: We reviewed 6,159 consecutive ambulatory patients with chronic heart failure between 2001-2006 and examined changes in RDW values from baseline to 1-year follow-up. Clinical, demographic, laboratory, and ICD-9 coding data were extracted from electronic health records, and all-cause mortality was followed over a mean follow-up of 4.4 ± 2.4 years. In this study cohort, median baseline RDW was 14.9%. RDW >16% at baseline (18.5% of cohort) was associated with a higher mortality rates than RDW ≤16%. For each +1% increment of baseline RDW, the risk ratio for all-cause mortality was 1.17 (95% confidence interval [CI] 1.15-1.19; P < .0001). At 12-month follow-up (n = 1,601), a large majority of subjects (68% in first tertile, 56% in second tertile of baseline RDW) showed rising RDW and correspondingly higher risk for all-cause mortality (risk ratio for +1% increase in changes in RDW was 1.08 (95% CI 1.03-1.13; P = .001). This effect was independent of anemia status or other baseline cardiac or renal indices, and particularly strong in those with lower baseline RDW. CONCLUSIONS: In our ambulatory cohort of patients with chronic heart failure, baseline and serial increases in RDW were associated with poor long-term outcomes independently from standard cardiac, hematologic, and renal indices.