Desired Time in Bed Independently Predicts Subjective Memory Complaints in Obstructive Sleep Apnea

Background and Objective Although obstructive sleep apnea (OSA) has been linked to cognitive complaints, the severity of objective disease often does not fully account for subjective memory complaints. This study aimed to investigate whether desired time in bed (dTIB) is associated with, and independently predicts subjective memory complaints in patients with OSA.Methods This study analyzed data from a prospective case-control study conducted at the Veteran Health Service Medical Center, Seoul, from August 2021 to December 2023. Out of 127 participants who underwent nocturnal polysomnography, self-report questionnaires, and clinical interviews, 92 individuals meeting diagnostic criteria for OSA were included in the final analysis.Results Among the 92 participants, 87.0% were male, with a mean age of 66.90±12.76 years and an Apnea-Hypopnea Index (AHI) of 45.78±23.26 events/hr. Participants reported mean Insomnia Severity Index (ISI) scores of 12.18±6.93, Beck Depression Inventory-II (BDI-II) scores of 13.97±9.20, and Subjective Memory Complaints Questionnaire (SMCQ) scores of 4.95±3.82. SMCQ scores showed significant correlations with age, BDI-II, total sleep time, dTIB, and desired total sleep time. After controlling for age, sex, body mass index, AHI, ISI, BDI-II, and wake after sleep onset, a longer dTIB remained an independent predictor of subjective memory complaints (B=1.00, p=0.017, ΔR²=0.05).Conclusions Longer dTIB was independently associated with subjective memory complaints, while objective OSA severity was not. These findings suggest that subjective memory complaints in OSA may be more closely linked to maladaptive sleep-related perceptions and behavioral factors than to objective respiratory disturbance itself.