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.

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.

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).

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.

This study investigates the role of RDW as a biomarker for pulmonary hypertension in at risk populations. The use of an easily obtainable biomarker for detecting may help to detect pulmonary hypertension in patients in early stages allowing for earlier treatment, better outcomes and better quality of life.