Red blood cell distribution width as an independent predictor of all-cause mortality in out of hospital cardiac arrest.

OBJECTIVE: Post-resuscitation period is characterized by high early mortality due to post-cardiac arrest syndrome. Recent studies found that elevated red cell distribution width (RDW) is a strong predictor of mortality in critically ill patients. We investigated the prognostic significance of RDW in out-of-hospital cardiac arrest (OHCA) victims.
METHODS: Analysis of emergency department OHCA registry extending from January 2007 to December 2010 was conducted. Patients with ROSC were assessed for Utstein predictors including sex, age, arrest location, presence of witness, bystander cardiopulmonary resuscitation, response time, initial rhythm and cause of arrest. RDW, hematocrit, white blood cell and platelet counts, blood urea nitrogen (BUN), creatinine and albumin were also obtained. Outcome variable was survival duration within 30 days. RDW was categorized in quartiles as <13.2%, 13.2% to 14.0%, 14.1% to 15.4% and >15.4%. Hazard ratios (HRs) were estimated using Cox-proportional hazard models in both univariate and multivariate analysis. All prognostic variables with their p value<0.1 in univariate analysis were used in multivariate analysis for adjustment.
RESULTS: Among 409 OHCA patients, 219 patients had ROSC. Highest RDW quartile (RDW>15.4%), female sex, older age, non-shockable initial rhythm, increased BUN and creatinine and decreased albumin, hematocrit and platelet count were associated with increased mortality in univariate analysis. In multivariate analysis, the highest RDW quartile was independently associated with all-cause mortality (HR=1.95; 95% CI 1.05-3.60; p=0.034) during 30-day post-resuscitation period. Other significant variables were age, initial rhythm and serum albumin.
CONCLUSIONS: Initial RDW is an independent predictor of all-cause mortality in post-resuscitation patients.