Use of hypnotics and the risk of or mortality from heart disease: a meta-analysis of observational studies

Some observational epidemiologic studies have reported conflicting results on the relationship between hypnotics use and the risk of developing and/or dying from heart disease. We investigated these associations using a meta-analysis of available literatures. We searched the databases PubMed and EMBASE, along with the bibliographies of relevant articles to find additional publications in February 2016. Of 495 articles satisfying our initial criteria, two case-control studies and six cohort studies met our inclusion criteria and were included in the final analyses. Compared with never having used any kind of hypnotics, the odds ratio for overall use was 0.84 for risk of or mortality from heart disease (95% confidence interval, 0.79 to 0.89) in a random-effects meta-analysis of all eight studies. With respect to the geographical region, use of hypnotics was associated with a decreased risk or mortality of heart disease in Asia but not in Western countries. Among various types of sleep medications, zolpidem showed a decreased risk (-29%) of developing or dying from heart disease, but benzodiazepines were related with an increased risk (80%) of or mortality from heart disease. The current meta-analysis of observational epidemiological studies suggested an evidence of association between hypnotics use and a decreased risk of heart disease.