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