Red cell distribution width as a novel predictor of mortality in ICU patients

Background. The red cell distribution width (RDW) in ICU patients has never been investigated. Methods. A total of 602 consecutive patients were prospectively enrolled. We collected each patient's base-line characteristics including the Acute Physiology and Chronic Health Evaluation II (APACHE-II) score, RDW, and C-reactive protein (CRP). The primary outcome for this analysis was ICU mortality, and secondary outcome was the total length of stay in hospital (TLSH). Potential predictors were analyzed for possible association with outcomes. Results. There was a significantly graded increase in APACHE-II score (tertile I = 10.7 +/- 6.5 versus tertile II = 13.3 +/- 6.2 versus tertile III = 15.8 +/- 7.2; all P < 0.001) and ICU mortality rate (tertile I = 11.2% versus tertile II = 18.8% versus tertile III = 33.8%; all P < 0.001) across increasing of RDW tertile. As compared with APACHE-II score, combination of RDW and APACHE-II score increased the area under the curve (AUC) for predicting ICU mortality from 0.832 +/- 0.020 to 0.885 +/- 0.017 (P < 0.05). Multivariate analysis demonstrated that RDW, APACHE-II score, and CRP were independent predictors of ICU mortality (P < 0.05). RDW was also independently associated with TLSH in patients alive (P < 0.05). Conclusion. We found a graded independent relation between higher RDW and adverse outcomes in ICU patients. RDW has the potentially clinical utility to predict outcome in ICU patients.