1017 Healthy Sleep, Healthy Mind: Examining the Relationship Between Objective Sleep Measures and Delirium Development

Introduction Delirium is a sudden, transient, but reversible neurological condition as a result of acute stressors, such as hospitalization for surgery or acute illness, and predisposed by many underlying conditions, including age, cognitive decline, and multiple comorbidities. We recently showed that self-reported sleep disturbances prior to surgery or illness are associated with an increased risk of delirium. The current study aimed to test whether objective sleep measures derived from actigraphy predict incident delirium. Methods Using the UK Biobank, we analyzed actigraphy data of ~ 7 days collected from 57,556 middle-older aged UK Biobank participants who had at least one hospitalization event during follow-up of up to 8 years. Four measures were extracted from the actigraphy data to objectively define daily sleep behavior: overnight sleep duration (between 9pm-7am), wake after sleep onset (WASO), daytime sleep duration (between 9am-7pm), and daytime sleep frequency. Cox proportional hazards models analyzed whether these sleep behaviors predicted an increased risk of incident delirium defined using the IDC-10 coding (specifically, code F05). Results In total, 606 individuals developed delirium (10.5/1,000) after the actigraphy assessment. A U-shaped relationship between overnight sleep duration and delirium risk was observed: short (< 7h) overnight sleepers (OR 1.23, 95% CI: 1.02-1.49, p=0.029) and long (>8h) overnight sleepers (OR 1.44, 95% CI: 1.01-2.04, p=0.043) had greater relative risk compared to 7-8h sleepers. Participants with longer daytime sleep duration (OR 1.46, 95% CI: 1.35-1.59, p< 0.001) and more frequent daytime sleep (OR 1.15, 95% CI: 1.11-1.18, p< 0.001) also showed an increased risk of delirium development. WASO was not significantly associated with the risk of delirium development. Conclusion Nocturnal sleep duration, daytime sleep duration, and daytime sleep frequency were associated with an increased risk for delirium. Further studies are required to confirm the present results, understand the underlying pathophysiology behind the relationship, and test whether optimizing sleep health can reduce the risk of developing delirium. Support (if any) Dr. L Gao is funded by the NIH grant R03AG067985 and the Alzheimer’s Association Clinician Scientist Fellowship (AACSF) grant AACSF-23-1148490