Patients with comorbid chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea syndrome (OSA) have greater decline in functional performance and autonomic imbalance at 1 year compared with COPD alone. These are the findings of a study published in the journal Heart & Lung.
Both COPD and OSA are associated with functional limitations and exercise intolerance. Some evidence suggests that the co-occurrence of OSA and COPD may be associated with even poorer outcomes than either alone.
Researchers conducted a prospective, observational study and recruited patients with COPD (n=17) and OSA-COPD (n=17) at centers affiliated with the Federal University of Sao Carlos in Brazil between 2017 and 2020. Study participants underwent clinical evaluation, lung function test, echocardiography, home sleep examination, and the 6 minute walk test (6MWT) at baseline and 12 months. Clinical and functional status were compared between patients with COPD with and without OSA.
At baseline, individuals in COPD and OSA-COPD cohorts included patients mean age, 63 (95% CI, 59-67) and 69 (95% CI, 65-73) years (P <.001), 41.2% and 82.4% were men, and they had body mass indexes (BMIs) of 22.5 (95% CI, 19.9-25) and 26.7 (95% CI, 23.5-30) kg/m2, respectively.
At baseline, individuals in the OSA-COPD group had significantly higher apnea and hypopnea index (mean, 18.5 vs 3.4 per hour; P <.001) and desaturation index during sleep (mean, 16.4 vs 5.9 per hour; P <.001) compared with individuals in the COPD cohort, respectively. Other lung and functional performance characteristics were well-balanced at baseline.
At the 1-year follow-up, individuals in the 2 groups had similar outcomes, except for 6MWT performance and autonomic responses during exercise. Those in the OSA-COPD group had lower performance (P =.003), achieved a lower percentage than expected (P =.003), and had a lower workload during exercise (P =.006) coupled with lower high frequency power (P =.03), low frequency over high frequency power (P =.03), and entropy (P =.04) during exercise compared with individuals in the COPD group.
In general, more patients with OSA-COPD had an exacerbation of symptoms (64.7%) compared with COPD alone (23.5%).
Patients with COPD who had co-occurring OSA were at increased risk for hospitalization (relative risk [RR], 1.44; P =.01) and achieved only 80% of the predicted 6MWT at 1 year (RR, 1.01; P =.04).
The major limitation of this study was the small sample size, however, the COVID-19 pandemic interfered with patient recruitment.
These data indicated that co-occurring OSA and COPD likely exacerbated clinical and functional outcomes. The researchers concluded, “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 alternatives.”
Camargo PF, Ditomaso-Luporini L, de Carvalho LCS Jr, et al. Obstructive sleep apnea reduces functional capacity and impairs cardiac autonomic modulation during submaximal exercise in patients with chronic obstructive pulmonary disease: A follow-up study. Heart Lung. 2023;57:257-264. doi:10.1016/j.hrtlng.2022.10.007