RESUMO
BACKGROUND: Impaired sleep quality and daytime sleepiness have been described in patients with primary biliary cirrhosis (PBC). However, no information is available on their sleep timing/diurnal preference. AIMS: To evaluate such variables and determine their relationship with sleep quality, fatigue, pruritus and quality of life. METHODS: Seventy-four patients with PBC (58 ± 12 years), 79 healthy volunteers (56 ± 8 years) and 60 patients with cirrhosis (58 ± 12 years) underwent formal assessment of sleep quality/timing, diurnal preference and daytime sleepiness. Patients with PBC also underwent assessment of fatigue, quality of life and the daytime course of sleepiness/pruritus. RESULTS: Sleep timing was significantly delayed in both patients with PBC and with cirrhosis, compared to healthy volunteers (sleep onset time: 23:18 ± 01:00 vs. 23:30 ± 01:00 vs. 22:54 ± 00:54 hours, respectively; P < 0.05). In patients with PBC, delayed sleep timing was associated with impaired sleep quality (P < 0.05). Sleepiness showed a physiological daily rhythm, with early afternoon/evening peaks. Pruritus was absent in the morning and increased over the afternoon/evening hours. Both the daytime course of pruritus and sleepiness changed in relation to diurnal preference. Patients with PBC and significant pruritus (upper quartile) had prolonged sleep latency (39 ± 37 vs. 21 ± 23 min, P = 0.05) and earlier wake-up times (5.9 ± 0.8 vs. 6.7 ± 0.9 min, P < 0.05). Significant correlations were observed between sleep timing and quality of life. CONCLUSIONS: Patients with PBC exhibited a delay in sleep timing that was associated with impaired sleep quality/quality of life. In addition, an interplay was observed between diurnal preference and the daytime course of pruritus/sleepiness.