More Than 1 in 3 PH Patients Found to Have Obstructive Sleep Apnea
PH plus apnea linked to higher risk of diabetes, high blood pressure
Obstructive sleep apnea (OSA) is common among people with pulmonary hypertension (PH), and PH patients with OSA are more likely to report co-occurring health problems like diabetes and high blood pressure, a new study done at a center in China reports.
In fact, the study found that more than one of every three PH patients had this type of sleep apnea, in which breathing completely stops when a person is sleeping.
“These findings highlight the importance of OSA as a modifiable target for optimal treatment in PH with comorbidities [co-occurring conditions],” the researchers wrote.
The study, “The comorbidity burden and disease phenotype in pre-capillary pulmonary hypertension: The contributing role of obstructive sleep apnea,” was published in the journal Sleep Medicine.
Investigating obstructive sleep apnea in PH
OSA is a common disorder, especially among middle-age and older adults, where the airway becomes obstructed during sleep, causing a person to temporarily stop breathing. This can cause low oxygen levels and inflammation, and OSA is a known risk factor for several cardiovascular diseases.
While sleep apnea is a known cause of pulmonary hypertension, the relationship between OSA and PH has not been investigated to date. Reports had suggested an increased prevalence or likelihood of co-existing medical conditions, called comorbidities, among people with pulmonary hypertension and obstructive sleep apnea.
To learn more, scientists in China assessed the prevalence of OSA among 450 PH patients who were assessed at Fuwai Hospital, in Beijing, between 2020 and 2021. About two-thirds of the patients were female, and the overall median age was 47 years.
All of the patients had pre-capillary forms of PH. This means their disease was caused by structural changes in pulmonary blood vessels leading to increased resistance to blood flow.
Most participants had been diagnosed with pulmonary arterial hypertension (70.2%) or chronic thromboembolism pulmonary hypertension (21.6%).
“To our knowledge, this is the first study to explore the relationship between the prevalence of key comorbidities and OSA in pre-capillary PH,” the scientists wrote.
Based on sleep respiratory studies, more than one in three (34.2%) pre-capillary PH patients had OSA — in fact, OSA was the most common comorbidity reported among the patients.
Other common co-occurring conditions included high blood pressure (21.6%), enlargement of the left upper chamber of the heart (19.1%), and diabetes mellitus (15.3%). High levels of fat in the blood (13.1%) and obesity (12.7%) also were found.
The prevalence of moderate-to-severe OSA and severe OSA were 11.8% and 3.3%, respectively.
“OSA was one of the most common clinical conditions in every age group of pre-capillary PH … However, OSA is largely under-recognized and under-treated in clinical practice,” the researchers wrote.
This findings led researchers to recommend that “more attention should be paid to OSA in the management of PH.”
People with OSA were older and more likely to be male. They also tended to have higher body mass index (a measure of body fat) compared with patients without OSA.
Statistical models showed that OSA was significantly associated with higher rates of obesity, high blood pressure, and diabetes, and the risk of these comorbidities tended to increase with more severe OSA.
According to the researchers, OSA likely contributes to these comorbidities, and these co-existing conditions may worsen obstruction sleep apnea in a “vicious circle.”
Rates of atypical pre-capillary PH, where the left side of the heart shows signs of damage, were significantly higher among patients with OSA than in those without OSA (18.8% vs. 2%), and statistical models showed a significant association between OSA and this atypical phenotype.
The researchers noted that people with atypical PH “respond differently to PAH targeted therapies,” so “a comprehensive evaluation of the phenotypic characteristics of PH patients, including individual factors and comorbidities, is necessary for clinicians to provide the optimal treatment.”
Noting that this was a study done at one center, the researchers called for further investigations into how OSA affects PH, and whether interventions to address OSA may help to ease PH or other comorbidities.
One possible treatment is the use of a continuous positive airway pressure (CPAP) machine, according to researchers, though “further studies are needed to better define the impact of CPAP treatment in concurrent PH and OSA patients.”
Such studies should focus on managing the burden of PH and comorbidities, the team said.
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