title: The burden of insomnia in Japan.
abstract: OBJECTIVE
  Several studies have suggested that patients who experience insomnia report a number of significant impairments. However, despite this literature, fewer studies have focused on the burden of insomnia among patients in Japan. The objective of the current study is to extend this work in Japan to further understand the effect of insomnia on health-related quality of life (hrQOL). Further, another objective is to understand general predictors of hrQOL among patients with insomnia.
  
  
  METHODS
  Data from the 2012 Japan National Health and Wellness Survey, an annual, cross-sectional study of adults aged 18 years or older, were used (N=30,000). All National Health and Wellness Survey respondents were categorized based on the incidence of self-reported insomnia diagnosis and prescription medication usage (clinical insomniacs under treatment versus [vs] good sleepers without insomnia or insomnia symptoms). Comparisons among different groups were made using multiple regression models controlling for demographics and health history.
  
  
  RESULTS
  Clinical insomniacs (n=1,018; 3.4%) reported significantly worse hrQOL compared with good sleepers (n=20,542) (mental component summary: 34.2 vs 48.0; physical component summary: 48.0 vs 52.8; health utilities: 0.61 vs 0.76; all P<0.05). Health behaviors (smoking, exercise, alcohol use) and comorbidities were the strongest predictors of health utilities for clinical insomniacs. For all three clinical insomniac subgroups of interest, those with a physical comorbidity but not a psychiatric one, those with a psychiatric comorbidity but not a physical one, and those without either a physical or psychiatric comorbidity, large decrements in health utilities were observed for respondents who did not engage in any positive health behaviors (0.61, 0.57, 0.64, respectively) relative to good sleepers (0.78). However, the gap in health utility scores between these subgroups and good sleepers diminishes with an increasing number of positive health behaviors (eg, clinical insomniacs with a physical comorbidity but not a psychiatric comorbidity performing all three positive health behaviors =0.67 vs good sleepers =0.78).
  
  
  CONCLUSIONS
  A significant burden remains for those with insomnia who are treated. Given the particularly low levels of hrQOL among treated insomnia patients who have poor health behavior profiles and have psychiatric comorbidities, physicians should place particular emphasis on these patients who are most in need of intervention. Improved treatments may help to address the unmet needs of these patient populations.
authors.affiliation: Department of Psychophysiology, National Institute of Mental Health, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Mishima
authors.affiliation: Kantar Health, New York, NY, USA.
authors.forename: Marco daCosta
authors.initials: Md
authors.lastname: DiBonaventura
authors.affiliation: Kantar Health, New York, NY, USA.
authors.forename: Hillary
authors.initials: H
authors.lastname: Gross
keywords: health behaviors; insomnia; quality of life