From the Journals

OSA overlap impairs functional performance in COPD



Obstructive sleep apnea (OSA) was associated with both impaired functional performance during exercise and overall worse outcomes in patients with chronic obstructive pulmonary disease (COPD), based on data from 34 adults.

Individuals with COPD are at increased risk for hospital readmissions and disease exacerbations, Patricia Faria Camargo, PhD, of Federal University of São Carlos (Brazil), and colleagues wrote. These patients often have concomitant obstructive sleep apnea, which itself can promote adverse cardiovascular events, but the impact of the overlap of these two conditions on clinical outcomes has not been explored.

In a study published in Heart & Lung, the researchers recruited 17 adults with COPD only and 17 with OSA and COPD. At baseline, patients underwent pulmonary function tests, echocardiography, and polysomnography to confirm their OSA and COPD diagnoses.

The primary endpoint was the impact of OSA on functional performance and cardiac autonomic control in COPD patients, based on measures of heart rate variability and the 6-minute walk test (6MWT). Participants were followed for 1 year, with telephone contacts every 3 months. A secondary endpoint was the number of exacerbations, hospitalizations, and deaths. At baseline, OSA-COPD patients had worse polysomnographic function, compared with COPD patients; they also tended to be older and have higher body mass index, but other demographics were similar between the groups.

Overall, patients in the OSA-COPD group had significantly greater functional impairment, compared with the COPD group (P = .003), as measured by the 6MWT. The OSA-COPD patients also showed significantly worse autonomic response during exercise, compared with the COPD group.

A lower work load during exercise and the interaction between group and time factors suggests that OSA impacts the exercise capacity of COPD patients, the researchers said. Notably, however, neither age nor body mass index was associated with functional performance in the OSA-COPD group.

Patients in the OSA-COPD group also were significantly more likely to experience exacerbations during the study period, compared with the COPD-only group (67.4% vs. 23.5; P = .03). However, the severity of COPD was similar between the groups, which further illustrates that OSA can impair functional performance in COPD patients, the researchers said.

The findings were limited by several factors including the small sample size and restricted collection of follow-up data during the pandemic, the researchers noted. However, the results support previous studies, and suggest that overlapping OSA and COPD produces worse outcomes.

“Future studies can confirm our findings, providing new clinical evidences to the assessment of sleep quality in COPD patients and its implications for the general health status of these individuals, in addition to contributing to more assertive clinical and therapeutic alternative support the need for more research into the mechanisms behind this overlap in larger samples to develop treatment alternatives,” they concluded.

The study was supported by the Federal University of Sao Carlos. The researchers had no financial conflicts to disclose.

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