Original ArticleChronic insomnia, quality-of-life, and utility scores: Comparison with good sleepers in a cross-sectional international survey
Introduction
Insomnia is defined as difficulty initiating sleep, difficulty maintaining sleep, morning awakening, or sleep that is chronically non-restorative or poor in quality associated with daytime impairment such as fatigue, memory impairment, social or vocational dysfunction, or mood disturbance [1], [2]. Chronic insomnia (with a duration of at least 1 month) is the most prevalent sleep disorder in the general population and is reported by 20–30% of adults. It is shown that insomnia increases with age and is more prevalent in women than in men [3], [4], [5], [6].
Chronic insomnia not only interferes with an individual’s health [2], but also confers a substantial socio-economic burden, given associations with falls and other accidents [7], decreased cognitive functioning, health-related quality of life (HRQoL) [8], increased absenteeism [9], [10], and increased utilization of medical resources [10], [11], [12]. Yet research on this issue has been limited [2]. Previous studies using the 36-item Short Form Health Survey of the Medical Outcomes Study (SF-36) reported that insomnia was associated with a negative impact across all dimensions of HRQoL, increasing with severity of disease [13], [14], [15], [16]. However, to our knowledge, there is no multi-country study of HR-QOL and utilities in insomnia.
The concepts of quality-adjusted life years (QALYS) and utilities are the basis for expressing the burden of disease and evaluating the cost effectiveness of therapeutic interventions. QALYs, the product of the average years of life that remain for the patient and the utility of those years based on associated HRQoL, is commonly used for comparative cost effectiveness analyses [18]. Utility measurement is a method of determining an individual’s preference for a certain outcome represented by a quantitative score: from perfect health (1) to death (0). Given the importance of understanding common patient characteristics independent of their cultural expression [18], [19], [20], and that the prevalence of insomnia varies between countries [21], this cross-sectional survey was performed in the USA, France, and Japan to obtain information relating to HRQoL and utility scores in people with chronic insomnia in different countries.
Section snippets
Design
SLEEPi (Study Linking European–US–Japanese Economic Perceptions in Insomnia – internet-based) was a cross-sectional, web- and paper-based questionnaire survey in three industrialized countries (the US, France, and Japan).
Participants
Participants were recruited on-line in the USA and France from the Harris Poll and Ciao (France only) market research panels, consisting of individuals who had voluntarily registered and agreed to regularly complete research surveys on a variety of topics. Between December 2005
Population characteristics
Fig. 2 shows the flow of participants in the study. The study population comprised 4067 individuals, of whom 2085 (48.7%) had chronic insomnia; 832 (39.9%) patients with insomnia were currently treated.
Demographic and clinical characteristics of participants with chronic insomnia and good sleepers are summarized by country in Table 1. The proportion of older respondents (>60 years) with chronic insomnia was higher in the US and Japanese cohorts (35% and 39%, respectively) than the French cohort
Discussion
The results of this study are consistent with prior observations [13], [14], [15], [16] that chronic insomnia is associated with impairment in HRQoL and lower utility scores (P < .0001 in each country) compared with good sleepers. Across all three countries, people with chronic insomnia (including those receiving treatment) reported lower SF-36 scores in each of eight domains compared with good sleepers (P < .0001), with greatest impact on the vitality, social functioning, role-emotional, and
Author contributions
Pr. Léger had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design
Léger, Morin, Uchiyama, Kobayashi, Cure, Walsh.
Acquisition of data
Cure, Hakimi
Analysis and interpretation of data
Léger, Morin, Uchiyama, Cure, Walsh.
Drafting of the manuscript
Léger, Hakimi.
Critical revision of the manuscript for important intellectual content
Léger, Morin, Uchiyama, Cure, Walsh.
Statistical expertise
Cure.
Financial disclosures
Pr. Léger reports that he has received honoraria from Sanofi Aventis as scientific advisor. Dr. Morin reports that he has received honoraria and/or Grant support from Sanofi Aventis as scientific advisor. Dr. Uchiyama reports that he has received honoraria and/or Grant support from Sanofi Aventis as scientific advisor. Dr. Hakimi, reports that he was an employee of Sanofi-Aventis. Ms. Cure reports that she has received Grant support from Sanofi-Aventis. Dr. Walsh reports that his institution
Funding/support
This research was funded by sanofi-aventis recherche and développement, Paris, France, which manufactures zolpidem and zopiclone.
Role of the sponsor
Sanofi-Aventis employees worked collaboratively with the investigators in designing the study and interpreting the data and were involved in the conduct of the study, including the collection, management, and initial analysis of the data. Sanofi-Aventis employees provided comments on the manuscript, but the writing committee made final decisions on the interpretation of study results and contents of the manuscript.
Previous presentation
Preliminary data was presented at the 14th Annual Conference of the International Society for Quality of Life Research, October 10–13, 2007, Toronto, ON, Canada.
Conflict of interest
The ICMJE Uniform Disclosure Form for Potential Conflict of interest associated with this article can be viewed by clicking on the following link: doi:10.1016/j.sleep.2011.03.020.
Acknowledgment
We thank the patients for their participation in this survey.
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