Factors associated with sleep state misperception in patients with obstructive sleep apnea.

PURPOSE: Little is known regarding the prevalence of sleep state misperception and the factors related to this in patients with obstructive sleep apnea (OSA).

METHODS

This retrospective study included patients with OSA defined by an apnea-hypopnea index (AHI) of ≥ 5 and used the Insomnia Severity Index (ISI), the Epworth sleepiness scale, the Patient Health Questionnaire-9, and the Generalized Anxiety Disorder-7. Underestimation and overestimation of sleep state perception were defined as < 80% and > 120%, respectively, of the ratio between subjective and objective total sleep time. An ISI score > 14 indicated clinically significant insomnia and an AHI ≥ 30 indicated severe OSA. A multinomial logistic regression was conducted with the category of sleep state perception as an outcome variable.

RESULTS

Of the 707 patients with OSA, underestimation and overestimation of sleep state perception were noted in 22.5% and 10.6% of subjects, respectively. The median absolute differences (and percentages of the ratio) between subjective and objective total sleep time were 116 min (66.9%) and 87 min (127.3%) in the underestimated and overestimated perception groups, respectively. In the adjusted model, the underestimated group was more likely to have an ISI score > 14 (OR = 1.812, P = .006). The overestimated group was more likely to be older (OR = 1.025, P = .025) and has severe OSA (OR = 1.729, P = .035).

CONCLUSIONS

There are two patterns of sleep state misperception in patients with OSA: underestimation associated with comorbid insomnia symptoms and overestimation associated with severe OSA. These findings enhance understanding of the pathophysiology of sleep state misperception in patients with OSA.