Factors Related to Sleeping Disorder Due to Pruritus in Patients with Chronic Liver Disease

OBJECTIVE: This study evaluated cases of pruritus, which is known to be associated with sleep disorder, in chronic liver disease (CLD) patients. METHODS: Questionnaires were given to 339 enrolled CLD outpatients in winter (November 2019 to March 2020) and again in summer (April to October 2020) (median interval: 104 days). Relative changes in symptoms shown by a visual analogue scale (VAS) and Kawashima's pruritus score between winter and summer were evaluated in Study 1 (n=199), while Study 2 examined the clinical features of patients with sleep disorder based on the results of the second questionnaire (n=235, median age 70 years old; 141 men, liver cirrhosis 37%). RESULTS: Study 1. There was a significant relationship in VAS between daytime and nighttime for each season, as well as between winter and summer for each time period (p<0.001). A comparison of Kawashima's pruritus scores for the daytime and nighttime showed no significant seasonal differences (p=0.436 and 0.828, respectively). When Kawashima's score increased, so did the average VAS for both daytime (0:1:2:3:4=0.4±0.2:1.4±0.9:3.0±1.8:5.9±2.1:6.2±2.3) and nighttime (0:1:2:3:4=0.3±0.1:1.4±1.5:3.5±2.3:6.7±2.6:6.9±1.8) (p<0.001 for both). Study 2. Twenty subjects (8.5%) complained of sleep disorder. An elevated FIB-4 index (≥3.07) showed a good predictive value for sleep disorder (p<0.01). The cut-off for the daytime and nighttime VAS values for existing sleep disorder were 1.6 [area under the curve (AUC) 0.901] and 3.4 (AUC 0.931). The respective sensitivity, specificity, and positive and negative predictive values for sleep disorder based on Kawashima's score (≥2) were 0.85, 0.28, 0.10, and 0.95 for the daytime and 1.00, 0.29, 0.12, and 1.00 for the nighttime. CONCLUSION: Intervention against pruritus is recommended in CLD patients with a high Kawashima's score (≥2) in any season, especially with an elevated FIB-4 index.