Red blood cell distribution width (RDW), a widely available biomarker, independently
predicts adverse outcomes in left-sided heart failure. The relation between RDW and
death in pulmonary hypertension (PH) is unknown. In a prospective study of 162 consecutive
patients with PH, RDW was recorded during initial diagnostic right-sided cardiac catheterization,
and patients were followed for 2.1 +/- 0.8 years to determine vital status. Demographic,
clinical, laboratory, and hemodynamic variables were compared by tertile of RDW. Cox
proportional-hazards models were used to determine whether RDW was independently associated
with death, and the prognostic utility of RDW was compared to that of other laboratory
predictors, including N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP). Of the
162 study patients, 78% were women, and 62% had pulmonary arterial hypertension. The
mean age was 53 +/- 15 years, and most patients had severe PH (mean pulmonary artery
pressure 48 +/- 13 mm Hg). The highest tertile of RDW predicted death (univariate
hazard ratio 4.86, 95% confidence interval 1.37 to 17.29, p = 0.015; multivariate
hazard ratio 2.4, 95% confidence interval 1.02 to 5.84, p = 0.045, after adjusting
for age, gender, diabetes mellitus, connective tissue disease, diuretic use, phosphodiesterase
inhibitor use, hemoglobin, mean corpuscular volume, and blood urea nitrogen [BUN]).
Of the laboratory data, only RDW, BUN, and NT-pro-BNP were associated with death on
univariate analysis. When RDW, BUN, and NT-pro-BNP were entered into a multivariate
model, only RDW was still associated with death (p = 0.037 for RDW, p = 0.18 for BUN,
and p = 0.39 for NT-pro-BNP). Adding NT-pro-BNP to RDW did not improve the prediction
of mortality. In conclusion, RDW is independently associated with death in patients
with PH and performs better as a prognostic indicator than NT-pro-BNP.