Prevalence of sleep disturbances and long-term reduced health-related quality of life after critical care: a prospective multicenter cohort study

INTRODUCTION: The aim of the present prospective multicenter cohort study was to examine the prevalence of sleep disturbance and its relation to the patient's reported health-related quality of life after intensive care. We also assessed the possible underlying causes of sleep disturbance, including factors related to the critical illness. METHODS: Between August 2000 and November 2003 we included 1,625 consecutive patients older than 17 years of age admitted for more than 24 hours to combined medical and surgical intensive care units (ICUs) at three hospitals in Sweden. Conventional intensive care variables were prospectively recorded in the unit database. Six months and 12 months after discharge from hospital, sleep disturbances and the health-related quality of life were evaluated using the Basic Nordic Sleep Questionnaire and the Medical Outcomes Study 36-item Short-form Health Survey, respectively. As a nonvalidated single-item assessment, the quality of sleep prior to the ICU period was measured. As a reference group, a random sample (n = 10,000) of the main intake area of the hospitals was used. RESULTS: The prevalence of self-reported quality of sleep did not change from the pre-ICU period to the post-ICU period. Intensive care patients reported significantly more sleep disturbances than the reference group (P < 0.01). At both 6 and 12 months, the main factor that affected sleep in the former hospitalised patients with an ICU stay was concurrent disease. No effects were related to the ICU period, such as the Acute Physiology and Chronic Health Evaluation score, the length of stay or the treatment diagnosis. There were minor correlations between the rate and extent of sleep disturbance and the health-related quality of life. CONCLUSION: There is little change in the long-term quality of sleep patterns among hospitalised patients with an ICU stay. This applies both to the comparison before and after critical care as well as between 6 and 12 months after the ICU stay. Furthermore, sleep disturbances for this group are common. Concurrent disease was found to be most important as an underlying cause, which emphasises that it is essential to include assessment of concurrent disease in sleep-related research in this group of patients.