The Role of Red Cell Distribution Width as a Predictor of Mortality for Critically Ill Patients in an Inner-city Hospital

BACKGROUND: Red cell distribution width (RDW) is a measure of the variation in the red blood cell volume that is usually recorded as a part of the standard complete blood cell count. Recent studies have demonstrated the prognostic value of RDW in many different clinical settings. The objective of this research study is to investigate the independent association of RDW with 30-day mortality in Intensive Care Unit (ICU) patients. METHODS: One hundred and fifty-six patients admitted to the ICU of our hospital between July 2009 and June 2011 were included in our study. Out of 156 patients, 124 survived the hospital stay. The data on patient's demographics, interventions done in ICU, and their comorbidities were collected. Baseline variables and the RDW value were compared between survivors and nonsurvivors. The cutoff point for RDW used for the comparison was 15.75. Both univariable and multivariable analyses were done. P < 0.05 was considered statistically significant. RESULTS: In the univariable analysis of the study between survivors and nonsurvivors, the median RDW was 17.20 for nonsurvivors, implying statistical significance (P = 0.007). In multivariable analysis, RDW remained significantly associated with inpatient mortality. The receiver operating characteristic is 0.656 (P = 0.007), with an optimal cutoff of 15.75 for RDW. At the cutoff of RDW, i.e., 15.75, the sensitivity and specificity for inpatient mortality was 71% and 89%, respectively. CONCLUSION: In critically ill ICU patients, RDW is an independent predictor of 30-day mortality. Taking into consideration the fact that RDW is routinely measured in complete blood count with no additional cost, this can serve as an “inexpensive prognostic marker” in critically ill patients.