The Role of Sleep Apnea in Postoperative Neurocognitive Disorders Among Older Noncardiac Surgery Patients: A Prospective Cohort Study

BACKGROUND: Obstructive sleep apnea is associated with increased dementia risk, yet its role in postoperative neurocognitive disorders is unclear. Here, we studied whether the severity of untreated obstructive sleep apnea is associated with the severity of postoperative neurocognitive disorder. METHODS: In this single-center prospective cohort study, older noncardiac surgery patients aged 60 years and above underwent preoperative home sleep apnea testing, and pre- and postoperative delirium assessments and cognitive testing. Sleep apnea severity was determined using the measured respiratory event index (REI). Global cognitive change from before to 6 weeks (and 1 year) after surgery was used to measure postoperative neurocognitive disorder severity. Postoperative changes in individual cognitive domain performance along with subjective cognitive complaints and/or deficits in instrumental activities of daily living were used to measure postoperative neurocognitive disorder incidence. RESULTS: Of 96 subjects who completed home sleep apnea testing, 58 tested positive for sleep apnea. In univariable analyses, sleep apnea severity was not associated with increased postoperative neurocognitive disorder severity at 6 weeks (global cognitive change ; [95% confidence interval [CI], -0.02 to 0.03]; P = .79) or 1-year after surgery (; [95% CI, -0.02 to 0.03]; P = .70). Adjusting for age, sex, baseline cognition, and surgery duration, sleep apnea severity remained not associated with increased postoperative neurocognitive disorder severity at 6 weeks (; [95% CI, -0.02 to 0.04]; P = .40) or 1-year after surgery (; [95% CI, -0.02 to 0.04]; P = .55). In a multivariable analysis, sleep apnea severity was not associated with postoperative neurocognitive disorder (either mild or major) incidence at 6 weeks (odds ratio [OR] = 0.89, [95% CI, 0.59-1.14]; P = .45) or 1-year postoperatively (OR = 1.01, [95% CI, 0.81-1.24]; P = .90). Sleep apnea severity was also not associated with postoperative delirium in univariable analyses (delirium incidence OR = 0.88, [95% CI, 0.59-1.10]; P = .37; delirium severity ; [95% CI, -0.02 to 0.03]; P = .79) or in multivariable analyses (delirium incidence OR = 1.07, [95% CI, 0.81-1.38]; P = .74; delirium severity OR = 0.95, [95% CI, 0.81-1.10]; P = .48). CONCLUSIONS: In this older noncardiac surgery cohort, untreated sleep apnea was not associated with increased incidence or severity of postoperative neurocognitive disorder or delirium.