Researchers developed a comprehensive and practical nomogram to predict the presence of obstructive sleep apnea (OSA) in patients with pulmonary arterial hypertension (PAH). They reported on their work in Nature and Science of Sleep.

OSA, which is characterized by repetitive airway obstruction during sleep, is associated with a number of cardiovascular diseases and recent studies have increasingly linked it to PAH. OSA is underrecognized and undertreated, despite recommendations for immediate referral of suspected OSA cases to a sleep center for further investigation. 

“In patients with PAH, the presence of OSA can induce a series of pathophysiological consequences including intermittent hypoxia, chronic inflammation, sympathetic stimulation, and alterations in intrathoracic pressure, which potentially contributes to the deterioration of pulmonary hemodynamics and ventricular function,” the authors of the study wrote. 

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They hence set out to investigate potential risk factors for OSA in patients with PAH and to create a nomogram for identifying patients at a higher risk of developing OSA. The team enrolled patients who were diagnosed with PAH via right-heart catheterization and had complete cardiorespiratory polygraphy data (polygraphy and polysomnography being major diagnostic tools for OSA). The participants were recruited between May 2020 and November 2021 from Fuwai Hospital in China. 

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Participants underwent various biochemical measurements, as well as nocturnal respiratory events evaluation. Sleep apnea was defined as either a complete cessation of airflow during sleep or a reduction of airflow of more than 90% for 10 seconds or more. 

Utilizing the data collected in the study, the researchers were able to develop a nomogram incorporating 6 factors: age, body mass index (BMI), hypertension, hemoglobin A1c (HbA1c), uric acid, and interleukin-6. Statistical analysis indicated that its performance in predicting patients at risk of OSA was satisfactory. 

“To our knowledge, this is the first study to develop a predictive model of OSA in PAH,” the authors of the study wrote. “Our findings will facilitate OSA risk assessment for patients with PAH, and therefore assist clinicians in referring patients for further diagnostic confirmation.” 


Hu M, Duan A, Huang Z, et al. Development and validation of a nomogram for predicting obstructive sleep apnea in patients with pulmonary arterial hypertensionNat Sci Sleep. 2022;14:1375-1386. doi:10.2147/NSS.S372447