Red blood cell distribution width as a related factor of pulmonary arterial hypertension in patients with systemic sclerosis

The aim of this study was to investigate the utility of red blood cell distribution width (RDW) as a simple and readily available marker of occurrence of pulmonary arterial hypertension (PAH) in patients with systemic sclerosis (SSc). One hundred and forty-five consecutive patients with SSc were recruited to the single-center cross-sectional study. Demographic characteristics, hematological parameters, Modified Rodnan Skin Score, and World Health Organization functional classification were determined. Diagnosis of PAH was based on screening by echocardiography and was confirmed by right heart catheterization. Interstitial lung disease (ILD) was diagnosed based on chest high-resolution computed tomography findings. There were no significant differences in gender, age, or disease duration between limited and diffused SSc groups. PAH was detected in 28 of lcSSc (33.3%) and 14 of dcSSc (23.0%) subjects. Patients with higher RDW values were more likely to be men with high anti-u1RNP titers and PAH. A significant correlation was found between RDW and high-sensitivity C-reactive protein (p = 0.375, p < 0.01) and the diffusing capacity of the lungs for carbon monoxide (ρ = − 0.396, p < 0.01). The SSc-PAH group had significantly higher RDW values compared to the SSc group without pulmonary disease (15.7 ± 2.2 and 13.7 ± 1.0, p < 0.001). The mean RDW in the SSc-PAH-ILD group was significantly higher than that in the SSc-ILD group (16.3 ± 2.2% and 14.0 ± 1.5%, p < 0.001). Besides the recognized risk factors, high RDW was an independent predictor of PAH in patients with SSc (OR = 3.314 [95%CI 1.038–10.580], p < 0.05). RDW may be a related factor for identifying the pulmonary arterial hypertension in SSc patients.