Examining the impact of obstructive sleep apnea on cognitive function in severe COPD

This study aimed to examine the association between obstructive sleep apnea (OSA) and cognitive function in patients with severe chronic obstructive pulmonary disease (COPD).

Patients with severe COPD, who had not previously been diagnosed with OSA, were recruited between January 2021 and January 2023. To evaluate cognitive function, the Montreal Cognitive Assessment (MoCA), a continuous reaction time test (CRT) and a driving simulator were used. OSA was identified using a CardioRespiratory Monitor (CRM). Cognitive tests were repeated for patients who were identified with and received treatment for OSA, to determine whether treatment improved cognitive function.

In total, 80 patients participated in the study and 50 patients (63%) were diagnosed with OSA, with or without nocturnal desaturation (ND), and six patients (8%) with ND only. Thirty-two patients (40%) had mild OSA and 18 (23%) had moderate/severe OSA. We found no statistically significant difference in the prevalence of cognitive impairment (CI) between patients with and without OSA and/or ND. However, a multiple regression analysis showed that patients with moderate/severe OSA had a significant lower CRT-index, indicating a decrease in attention and reaction time, compared to patients with mild OSA.

In patients with COPD and OSA, the degree of CI may depend on the severity of OSA. The 23% prevalence of moderate/severe OSA emphasizes the importance of OSA screening in severe COPD.

The study was registered at www.clinicaltrials.gov in March 2020, with the identification number NCT04458038.