A new study has assessed risk factors for the development of pulmonary arterial hypertension (PAH) in patients with mixed connective tissue disease (MCTD) and found red cell distribution width (RDW) to be a sensitive predictor.

The study, published in BMC Pulmonary Medicine, also observed left and right heart remodeling in this patient group.

“Pulmonary involvements, especially PAH, are devastating complications among patients with MCTD, resulting in increased morbidity and mortality,” the authors wrote. “The present study aimed to explore the factors associated with PAH in patients with MCTD and determine the diagnostic value of the identified factors.”

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The research team reviewed data on 119 patients with MCTD at a single center in China between May 2009 and December 2022. Of the 119, 46 were diagnosed with PAH based on a transthoracic echocardiography-estimated resting pulmonary arterial systolic pressure (PASP) of 36 mm Hg or higher. Demographic and disease activity data were collected.

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The median PASP of the patients with MCTD-PAH in this study was 67.0 mm Hg, which is significantly higher than the diagnostic threshold. In addition, these patients had significantly higher pericardial effusion values and lower indices of left ventricular diastolic dimension, pulmonary artery, left atrial diameter, and left ventricle ejection fraction, suggesting remodeling of the left heart as well as the right heart.

However, univariate and multivariate logistic regression analyses showed that only RDW was independently associated with PAH in this patient group. There was also a positive correlation between RDW and PASP. At a cutoff of 15.2%, the receiver operating curve for RDW diagnostic accuracy had 80.4% sensitivity and 82.2% specificity for diagnosing PAH.

The authors conclude that patients with MCTD with elevated RDW are at significant risk for PAH and that RDW could serve as a simple index for these patients in routine clinical practice.


Jin Y, Guo G, Wang C, Jiang B. Association of red cell distribution width with pulmonary arterial hypertension in patients with mixed connective tissue disease. BMC Pulm Med. Published online August 14, 2023. doi.10.1186/s12890-023-02597-z