Sleep problems in the community elderly as predictors of death and nursing home placement

In 1984-85, 1855 elderly residents of an urban community responded to a comprehensive baseline interview that included questions regarding an extensive set of sleep characteristics and problems. During the subsequent 3 1/2 years of follow-up, 16.7% of the respondents died and 3.5% were placed in nursing homes. The predictive significance of each sleep characteristic for mortality and for nursing home placement was determined separately for males and females, using Cox proportional hazards models. Selected demographic and psychosocial variables were also entered into the models. Age, problems with activities of daily living (ADL), self-assessed health, income, cognitive impairment, depression and whether respondents were living alone were controlled for statistically. Of the many variables analyzed, in males insomnia was the strongest predictor of both mortality and nursing home placement. For mortality, the relative hazard associated with insomnia exceeded the hazards associated with age, ADL problems, fair-poor health and low income. For nursing home placement, the hazard associated with insomnia exceeded that associated with cognitive impairment. The relationships of insomnia to mortality and nursing home placement were U-shaped, with a worse outcome if insomnia complaints over the preceding 2 weeks were either prominent (numerous or frequent) or absent. For females, insomnia was a borderline predictor of mortality and did not predict nursing home placement at all. Symptoms of the restless legs syndrome predicted mortality for females in some Cox regression models. Reported sleep duration, symptoms of sleep apnea and frequent use of hypnotic drugs did not predict mortality or nursing home placement in either sex.