547 Earlier-life sleep patterns and risk for delirium in elderly hospitalized patients from a 14-year longitudinal cohort

Abstract

Abstract Introduction Delirium is an acute decline in attention and cognition that is associated with cognitive dysfunction in elderly patients. While accumulating evidence points to associations between sleep disturbances and neurocognitive disorders, the temporal relationship between sleep patterns and delirium remains unclear. We tested whether earlier-life sleep duration, daytime dozing, insomnia, and sleep apnea predict incident delirium during hospitalization. Methods We studied 315,989 participants (mean age 58.3±7.9; range 37.4–73.7) from the UK Biobank with up to 14 years follow-up, and at least one hospitalization episode. Delirium diagnosis was derived using ICD-10 coding from hospitalization records. Multivariate logistic regression models examined the associations of self-reported baseline sleep duration (less than 6h/6-9h/more than 9h), daytime dozing (often/rarely), insomnia (often/rarely), and presence of prior sleep apnea (ICD-10), with incident delirium. Models were adjusted for age, sex, education, Townsend deprivation index, and major confounders (including number of hospitalizations during follow-up, BMI, neurological/cardiovascular/respiratory diseases, depression/anxiety, chronotype, and sedatives). Results 4,025 developed delirium (12.7/1,000). There was a U-shaped association between sleep duration and delirium, where short [17.3/1,000; OR 1.18, 95% CI: 1.05–1.33, p=0.006] and long (28.8/1,000; OR 1.49, 95% CI: 1.30–1.70, p<0.001) sleepers had elevated risk compared to regular 6-9h sleepers. Often daytime dozing (25.3/1,000; OR 1.38, 95% CI: 1.20–1.58, p<0.001) and sleep apnea (21.7/1,000; OR 1.21, 95% CI: 1.03–1.42 p=0.02) also had increased the risk for delirium, but the latter was attenuated by the inclusion of BMI and hypertension. However, we did observe further risk when two or more of the above traits were present (OR 1.59, 95% CI: 1.29–1.95 p<0.001). No effects on incident delirium were observed from insomnia. Conclusion Earlier-life sleep patterns, in particular longer sleep and daytime dozing, are associated with an increased risk for delirium. Sleep patterns may reflect unmeasured health status; further work is warranted to confirm the associations using objective sleep/circadian measures, examine underlying mechanisms, and test whether optimizing sleep patterns can reduce the risk of developing delirium. Support (if any) NIH [T32GM007592 and R03AG067985 to L.G. RF1AG059867, RF1AG064312, to K.H.], the BrightFocus Foundation A2020886S to P.L. and the Foundation of Anesthesia Education and Research MRTG-02-15-2020 to L.G.