OBJECTIVES

To determine whether sleep disruption at home or in hospital is an independent risk factor for postoperative delirium in older adults undergoing elective surgery.

DESIGN

Prospective cohort study.

SETTING

German teaching hospital.

PARTICIPANTS

Individuals aged 65 and older undergoing elective arthroplasty (N = 101).

MEASUREMENTS

Preoperative questionnaires were used to assess sleep disruption at home (Pittsburgh Sleep Quality Index). Actigraphy was used to objectively measure sleep disruption in the hospital before and after surgery. Delirium was assessed daily after surgery using the Confusion Assessment Method and, if there was uncertainty, validated according to International Classification of Diseases, Tenth Revision (ICD-10), criteria.

RESULTS

Twenty-seven participants developed postoperative delirium. Those with sleep disruption at home were 3.26 times as likely to develop postoperative delirium as those without (95% confidence interval (CI) = 1.34-7.92, P = .009). Participants with sleep disruption in hospital were 1.21 times as likely to develop postoperative delirium as those without (95% CI = 1.03-1.41, P = .02). When adjusting for other variables, risk remained significant for sleep disruption at home (risk ratio (RR) = 3.90, 95% CI = 2.14-7.11, P < .001) but not in the hospital (RR = 1.19, 95% CI = 0.69-2.07). Jointly modeling sleep disruption at home and in the hospital, adjusted for covariates, resulted in significant contributions of both (home: RR = 3.10, 95% CI = 1.34-7.17, P = .008; hospital: RR = 1.38 95% CI = 1.13-1.68, P = .002).

CONCLUSIONS

Older people with sleep disruption at home are at significantly higher risk of developing postoperative delirium than those without. Sleep disruption in the hospital may further heighten this risk.