Cognitive Reserve and Postoperative Delirium in Older Adults

Abstract

Objectives: To examine the role of cognitive reserve in reducing delirium incidence and severity in older adults undergoing surgery. Design: Prospective cohort study. Setting: Hospital. Participants: Older adults (mean age 71.2, 65% women) undergoing elective orthopedic surgery (N = 142). Measurements: Incidence (Confusion Assessment Method) and severity (Memorial Delirium Assessment Scale) of postoperative delirium were the primary outcomes. Predictors included early- (literacy) and late-life (cognitive activities) proxies for cognitive reserve. Results: Forty-five participants (32%) developed delirium. Greater participation in cognitive activity was associated with lower incidence (odds ratio = 0.92 corresponding to increase of 1 activity per week, 95% confidence interval (CI) = 0.86–0.98, P = .006) and severity (B = −0.06, 95% CI = −0.11 to −0.01, P = .02) of delirium after adjustment for age, sex, medical illnesses, and baseline cognition. Greater literacy was not associated with lower delirium incidence or severity. Of individual leisure activities, reading books, using electronic mail, singing, and computer games were associated with lower dementia incidence and severity. Conclusion: Greater late-life cognitive reserve was associated with lower delirium incidence and severity in older adults undergoing surgery. Interventions to enhance cognitive reserve by initiating or increasing participation in cognitive activities may be explored as a delirium prophylaxis strategy.