P1 Primary biliary cirrhosis: time for sleep

Abstract

Background: Abnormal sleep timing has been shown to impinge on prognosis (cancer development, death) in both health and disease. Impaired sleep quality and excessive daytime sleepiness have been described in patients with primary biliary cirrhosis (PBC). However, virtually no information is available on sleep timing or diurnal preference in this patient population. Aim: To assess sleep-wake rhythms in patients with PBC, particularly in relation to sleep quality and quality of life. Methods: Fifty patients with PBC and no liver cirrhosis (45 females; age 58±12 yrs; Mayo score 4.7±0.9) and 40 matched healthy controls (32 females; age 54±8 yrs) underwent assessment of habitual sleep quality (STSQS questionnaire), habitual daytime sleepiness (Epworth sleepiness scale), diurnal preference (morning vs. intermediate vs. evening preference), sleep timing (habitual bed time, sleep onset, sleep latency, number of night awakenings, wake-up-time and get-up time) and quality of life (SF36 questionnaire). Results: No significant differences in sleep quality, daytime sleepiness or diurnal preference were observed between patients with PBC and healthy controls. However, patients with PBC started to sleep later (23.3±1.0 vs. 22.9±0.9, p=0.02), had more night awakenings (2.0±1.1 vs. 1.5±1.2, p=0.03), woke up (6.9±1.0 vs. 6.3±0.7, p=0.004) and got up later (7.4±1.0 vs. 6.7±0.7, p=0.0001) compared to healthy controls. This held true when employment status (employed vs. unemployed/retired) was taken into account. Delayed sleep habits were associated with worse sleep quality (i.e. sleep onset vs. sleep quality: R=0.47, p<0.01). Quality of life was impaired in patients with PBC compared to healthy controls (SF36 physical component: 41±13 vs. 48±7, p=0.04; SF36 mental component: 45±8 vs. 49±8, n.s.). Significant correlations were observed between the SF36 mental component and sleep quality (R=0.80, p<0.01) and between the SF36 physical component and sleep timing (i.e. sleep onset: R=0.71, p<0.01). Patients with PBC and intermediate diurnal preference had better quality of life (SF36 physical component) than those with morning/evening preference (p<0.05). On multivariate analysis, sleep onset time was an independent predictor of the SF36 physical component (p<0.01); a trend was maintained (p<0.08) when the model included the Mayo score. Conclusions: Sleep timing was delayed in patients with PBC compared to healthy controls. This delay was associated with worse sleep quality and impaired quality of life. Should these results be confirmed, further studies into the pathogenesis/prognostic relevance of delayed sleep timing in this patient population would be worthwhile.