Red blood cell distribution width and mortality risk in critically ill cardiovascular patients.

Background: The association between red blood cell distribution width (RDW) and mortality risk in critically ill cardiovascular patients has not been well studied. Objective: To examine the association between RDW and 30-day all-cause and cause-specific mortality in critically ill cardiovascular patients. Methods: This cohort study included 47,266 patients from the eICU database. RDW was categorized as <13.0 %, 13.0-13.4 %, 13.5-13.9 %, 14.0-14.4 %, 14.5-14.9 %, ≥15.0 %. Logistic regression model was used to estimate adjusted odds ratios (ORs), and log-linear regression model was used to examine absolute rate differences (RDs) in mortality risk. Cubic spline curve was used to explore the nonlinear association between changes in RDW and mortality. Results: A graded association between higher RDW and incremental risk of death was observed. Compared with RDW of <13.0 %, the adjusted odds ratios for all-cause mortality were 1.29 (95 % CI, 1.10 to 1.53) for RDW of 13.5-13.9 %, 1.57 (95 % CI, 1.33 to 1.85) for RDW of 14.0-14.4 %, 1.94 (95 % CI, 1.64 to 2.29) for RDW of 14.5-15.0 %, and 3.15 (95 % CI, 2.74 to 3.63) for RDW of ≥15.0 %. The absolute rate differences for RDW of 13.5-13.9 %, 14.0-14.4 %, 14.5-14.9 %, and ≥15.0 % indicated an additional 6, 13, 14, and 40 deaths per 1000 patients, respectively. RDW was associated with most, but not all, cause-specific deaths. Conclusion: RDW was strongly associated with all-cause mortality and most cause-specific mortality in critically ill cardiovascular patients. These findings underscore the importance of this readily available hematologic indicator in mortality risk stratification.