Red Cell Distribution Width in Acute Pulmonary Embolism Patients Improves 30-Day Mortality Risk Stratification Based on the Pulmonary Embolism Severity Index

To validate red cell distribution width (RDW) as an improvement in 30-day mortality risk stratification based on the Pulmonary Embolism Severity Index (PESI) in acute pulmonary embolism (PE).Prospective observational analysis of consecutive adult acute PE patients.Among 731 patients, 30-day mortality was 11.9%. With adjustment for the PESI score and number of covariates, higher RDW was associated with higher mortality (RDW continuous: OR 1.21, 95% CI 1.06-1.38; Bayesian OR 1.22, 1.07-1.40; RDW 'high' [>14.5% in men >16.1% in women] vs normal: OR 3.83, 1.98-7.46; Bayesian OR 3.98, 2.04-7.68]. Crude mortality was 3.6% if PESI 86-105 (intermediate risk), but 1.2% if RDW normal and 7.1% if RDW high; 11.8% if PESI 106-125 (high risk), but 3.6% if RDW normal and 18.8% if RDW high. Adjusted probabilities showed higher mortality (ORs between 3.5-5.8) if RDW was high in any PESI risk subgroup. Crude mortality rates in two random-split subsets (n=365 and n=366) again showed the same patterns.On-admission RDW above the normal range improves 30-day mortality risk stratification based on PESI score in acute PE. Particularly, it corrects PESI-based intermediate-risk or high-risk allocation by reclassification into very low-risk (<3.5%) or very high-risk (>11.0%).