Association between the course of hypnotics treatment for insomnia and work functioning impairment in Japanese workers

Study objectives: This cross-sectional study analyzed the effect of treatment with hypnotics for sleep disorders, particularly insomnia, on daytime work functioning by phase of treatment in Japanese workers. Methods: Subjects were respondents (n = 36,375) to a questionnaire survey conducted in 2015 to assess work functioning impairment in 15 companies in Japan. The questionnaire results were analyzed together with the respondents’ healthcare data extracted from public health insurance claims. Work functioning impairment was measured using the Work Functioning Impairment Scale (WFun). The status of treatment for insomnia was determined using data on diseases and prescribed drugs extracted from health insurance claims from the past 16 months. The odds ratio of severe work functioning impairment according to on-treatment duration and off-treatment duration was estimated using logistic regression analysis. Results: The risk of severe work functioning impairment was significantly higher in subjects with insomnia who were being treated with hypnotics for 1 month or longer compared to non-insomnia subjects. This increased risk tended to be reduced with longer on-treatment duration. For subjects who had previously received hypnotics treatment for insomnia, the risk of severe work functioning impairment was significantly increased in all subgroups stratified by time from discontinuation of the prescription. This increased risk tended to be reduced with longer off-treatment duration. Conclusions: Workers who are or were receiving hypnotics to treat insomnia may have a higher risk of daytime functioning impairment. Those with protracted insomnia require careful assessment of the risks and benefits of prescription hypnotics.