Increased serum interleukin-6, not minimal hepatic encephalopathy, predicts poor sleep quality in nonalcoholic cirrhotic patients

Background: Sleep–wake disturbances are common in patients with cirrhosis and have a considerable effect on health-related quality of life; however, the underlying mechanism behind the phenomenon is unclear. Cytokines are involved in the mediation of signalling pathways regulating fibrogenesis, leading to cirrhosis. In addition, increased cytokines could contribute to sleep disturbances. Aim: To determine the relationship between pro-inflammatory cytokines and sleep disturbance in cirrhotic patients. Methods: Ninety-eight nonalcoholic cirrhotic patients without overt hepatic encephalopathy were enrolled in this cross-sectional study. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. The Psychometric Hepatic Encephalopathy Score (PHES) was used to examine cognitive performance and define minimal hepatic encephalopathy (MHE). The Hospital Anxiety and Depression Scale (HADS) was used to evaluate the mood status of the patients. Pro-inflammatory cytokines that include interleukin 6 (IL-6) and tumour necrosis factor-α, as well as HBV-DNA or HCV-RNA levels were determined in patients. Results: A total of 56 (57%) cirrhotic patients were identified as ‘poor’ sleepers (PSQI > 5). After multivariate analysis, IL-6 (P = 0.001) and HADS scores (P = 0.002) were found to be independent predictive factors of poor sleep quality. No significant relationships were observed between the sleep indices and the presence of MHE. HCV-RNA, but not HBV-DNA, viraemia was associated with sleep disturbance in cirrhotic patients. Conclusions: Sleep disturbance is found commonly in cirrhotic patients and a high serum IL-6 level is predictive of poor sleep quality. Minimal hepatic encephalopathy by itself may not contribute to sleep dysfunction in cirrhotic patients.