Patients with OSA, COPD frequently have cardiovascular disease

Key takeaways:

• In COPD and obstructive sleep apnea, nocturnal hypoxemia and airway inflammation contribute to cardiovascular disease.
• Research is needed on cardiovascular disease severity in COPD-OSA overlap.

Cardiovascular disease often occurs among patients with both COPD and obstructive sleep apnea, but there are little data evaluating how the overlap impacts disease severity, according to a presentation at the 2023 GOLD COPD conference.

“Patients who have underlying COPD … don’t sleep well,” Samuel Krachman, DO, director of the sleep center at Temple University Hospital Jeanes Campus and professor of thoracic medicine and surgery at Temple University’s Lewis Katz School of Medicine, said during his presentation. “They have other things that they’re concentrating on, including trying to breathe.”

According to Krachman, the frequency of COPD and OSA among adults is comparable, with COPD occurring among more than 10% of those aged 40 to 79 years and moderate to severe OSA occurring among 7% to 14% of those aged 30 to 70 years depending on sex.

COPD, OSA overlap

In terms of overlap of the two diseases, studies have shown that 11% of patients with OSA had obstruction and 14% of patients with mild obstructive disease had OSA, but Krachman said OSA in those with COPD is “no higher than in the general population” based on findings from larger studies.

Notably, the patient group and clinical setting may impact prevalence of OSA, as a single-center study found mild OSA (apnea-hypopnea index [AHI] > 5 events per hour) in over half (66%) of patients receiving pulmonary rehab for moderate to severe COPD.

Delving deeper into which patients with COPD also develop OSA, Krachman presented findings from one of his studies showing that AHI went down with more emphysema and gas trapping, which suggests that a larger lung volume “has a stabilizing effect on the upper airway.”

Phenotypes might also play a role in finding out how severe OSA is in COPD, Krachman said.

“One of the other parameters that was predictive of the AHI was the BMI, so maybe it is really a phenotype difference and not only just how hyperinflated or obstructed you are as far as the risk for developing overlap syndrome,” he said during his presentation.

Cardiovascular consequences

In both COPD and OSA, nocturnal hypoxemia and airway inflammation contribute to cardiovascular disease, according to Krachman.

Healio has previously reported that sleep apnea is a risk factor for cardiovascular mortality, and Krachman said this condition impacts the heart in several ways, including by raising left ventricular transmural pressure and afterload, raising venous return leads and causing pulmonary artery vasoconstriction through means of hypoxia.

When evaluating pulmonary artery pressure in OSA and COPD separately, patients with OSA had a mildly elevated pressures, and patients with COPD and nocturnal desaturation also showed minor rises in pressure, according to studies on each topic.

Among those with OSA, Krachman noted pulmonary hypertension in 12% to 34% of patients, and mild pulmonary hypertension (mean pulmonary artery > 20 mmHg) in 91% to 95% of patients with COPD.

Studies looking at how OSA-COPD overlap impacts pulmonary hypertension have found only a mild difference in pulmonary artery pressure when compared with OSA individually, but there are not many studies addressing this question, Krachman said.

Notably, a study presented at SLEEP 2023 found that more patients with OSA-COPD overlap vs. only COPD had pulmonary artery enlargement (66.7% vs. 28.6%; P = .033). Both sets of patients had comparable nocturnal hypoxemia and airflow obstruction; however, BMI was significantly higher in the overlap group, and Krachman said this could have impacted the main finding.

CPAP

Lastly, Krachman focused on the impact of CPAP among patients with disease overlap. According to a study published in American Journal of Respiratory and Critical Care Medicine, survival decreased among those not using CPAP compared with those using CPAP.

“We know from treatment of OSA alone, that there is a survival benefit there in regard to cardiovascular morbidity and mortality, so maybe it’s the OSA component that is leading the way in improved survival; that still needs to be worked out,” Krachman said.

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