Prevalence of restless legs syndrome in Japanese patients with chronic liver disease

Aim: Sleep disturbance is a major complication in patients with chronic liver disease, but causes are unclear. The aim of this study was to clarify the prevalence of restless legs syndrome (RLS) in Japanese chronic liver disease patients and investigate the influence on sleep and quality of life. Methods: The study included 149 consecutive outpatients with chronic liver disease at Nagasaki University Hospital between September 2008 and March 2010. The presence of RLS was evaluated by a written survey using the questionnaire for the epidemiological surveillance of the international RLS research group in 2003. In addition, 89 cases, including all RLS patients, were evaluated for sleep quality and health-related quality of life. Sleep quality was evaluated by using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI), and health-related quality of life was evaluated by the Japanese SF-36 Health Survey. Result: Twenty-five of the 149 patients (16.8%) fulfilled the diagnostic criteria for RLS. The median global PSQI score of the RLS group was significantly higher than the non-RLS group (9 vs 5, P<0.01). The number of poor sleepers (global PSQI score, >5) in the RLS group was significantly higher than in the non-RLS group (P<0.05). In SF-36, the mental component summary score of the RLS group was 43.8±10.8, which was significantly lower than the non-RSL group (49.8±10.5; P<0.05). Conclusion: This is the first report that clarifies the prevalence of RLS in Japanese chronic liver disease patients. RLS worsens quality of sleep and life in chronic liver disease patients.