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.