Severe obstructive sleep apnea in patients with chronic obstructive pulmonary disease is associated with an increased prevalence of mild cognitive impairment

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are associated with mild cognitive impairment (MCI). However, this association is unclear. This study aimed to assess the prevalence of MCI in patients with overlap syndrome, determine whether OSA increases the risk of MCI in patients with COPD, and investigate the potential mechanisms for this association. Participants with stable Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 2–4 COPD and complaints of snoring in 2016–2018 were enrolled in this cross-sectional observational study. All were free of asthma, acute left-sided congestive heart failure, unstable coronary heart disease, uncontrolled hypertension, diabetes, encephalitis, and epilepsy. They underwent pulmonary function tests and overnight polysomnography and completed the Montreal Cognitive Assessment (MoCA). MCI was defined by an MoCA score of