435P Hypnotics and risk of cancer: A meta-analysis of observational studies

Abstract

The association between hypnotic drugs and risk of cancer remains controversial. Therefore, we performed a meta-analysis to investigate this association. Pubmed and Embase were searched systematically were searched to identify publications up to May 2020. The Newcastle-Ottawa scale for observational studies was used to assess the quality of studies. All included studies were evaluated by two reviewers independently; any discrepancies were resolved through discussion. A total of 28 observational epidemiological studies including 22 case-control studies and 6 cohort studies with 340,614 hypnotics users and 1,828,057 non-users were included in the final analyses. Hypnotics (benzodiazepines and Z-drugs) use was significantly associated with an increased risk of cancer (odds ratio [OR] or relative risk [RR] 1.17; 95% confidence interval 1.09–1.26) in a random-effects meta-analysis of all studies. Subgroup meta-analyses by various factors such as study design, type of case-control study, study region, and methodological quality of study showed consistent findings. Also, a significant dose-response relationship was observed between the use of hypnotics and the risk of cancer. This meta-analysis revealed association between use of hypnotics drugs and risk of cancer. However, a high heterogeneity was observed among identified studies and results were inconsistent in some subgroups. Randomized control trials are needed to confirm the results in future.