A new study has revealed sexual dimorphism in regard to 6-minute walk distance (6MWD), hemodynamics, and body mass index (BMI) in patients with pulmonary arterial hypertension (PAH).

The study, published in the Annals of the American Thoracic Society, noted that female patients had shorter 6MWDs and less hemodynamic impairment than male patients and that these factors were modified by BMI.

“Gender and sexual dimorphism in pulmonary vascular disease have become a focus of clinical and experimental studies in recent years,” the authors wrote. “We aimed to examine whether sex (or gender) as reported on case report forms (CRFs) was associated with baseline values of 6MWD, hemodynamics, and functional class in clinical trial participants with PAH and, if present, whether these associations were modified by age and body mass index (BMI) using data from eighteen randomized clinical trials in PAH.”

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The research team analyzed data on 6633 patients from 18 randomized, controlled clinical trials investigating treatments for PAH between 1998 and 2013. Of these patients, 1436 were male, and at enrollment, 2491 were on background PAH therapy.

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The results showed that female patients had shorter 6MWDs than male patients and that for both sexes, increased age led to decreased 6MWD. As BMI increased in female patients, 6MWD decreased, but this did not occur in male patients.

Women had lower right arterial pressure and mean pulmonary arterial pressure than men. Male patients had higher cardiac output than female patients, and there were no significant differences found between age and cardiac output by sex.

The team concluded that as PAH treatment moves towards more individualized and precision-based approaches, considering these key characteristics and their interrelationships will contribute to the design of more appropriate clinical trials and effective treatment regimens for these patients.


Ventetuolo CE, Moutchia J, Baird GL, et al. Baseline sex differences in pulmonary arterial hypertension randomized clinical trials. Ann Am Thorac Soc. Published online September 2, 2022. doi:10.1513/AnnalsATS.202203-207OC