Use of red cell distribution width in a population at high risk for pulmonary hypertension.

Background: Pulmonary hypertension (PH) often presents with non-specific symptoms making early diagnosis difficult. Red cell distribution width (RDW) is a parameter routinely reported on an automated complete blood cell count that has been associated with numerous disease states. The purpose of this study was to further evaluate RDW as a biomarker for PH in at-risk populations.

Methods: In a retrospective, cross-sectional analysis of patients seen at a PH center over 1 year, we examined both patients with PH and patients at risk for but without PH (e.g. systemic sclerosis, [SSc]). We also studied a group of age-and sex-matched, non-diseased controls. Relevant characteristics were compared among the 3 groups using one-way ANOVA. Similar comparisons were made across World Health Organization (WHO) PH groups 1-4.

Results: RDW was highest in the PH patients (n = 181), intermediate in the at-risk for PH patients (n = 52), and lowest in matched controls (n = 100) (15.9 ± 2.8 vs 14.8 ± 2.8 vs 14.2 ± 1.1%, respectively; p < 0.0001). There were no significant differences in RDW across WHO PH groups (p = 0.50). SSc patients with PH had significantly higher RDW values compared to SSc patients without PH (16.0 ± 2.2 vs 14.4 ± 1.9%, respectively; p = 0.03).

Conclusions: RDW is significantly higher in PH patients, without regard to disease etiology, when compared to age- and sex-matched non-diseased controls. Importantly, RDW is also higher in PH patients compared to at-risk patients, particularly in the SSc cohort. The ease of obtaining RDW as a biomarker may help detect incident PH at earlier stages among patients who are at high risk for development of PH.