Objective: To systematically evaluate whether interventions targeted at improving sleep in intensive care units (ICUs) were associated with reduction in ICU delirium. Methods: We searched the Cochrane Library, PubMed, Embase, Web of Science, VIP, CNKI and Wanfang Data for randomized controlled trials on sleep interventions and delirium both at home and abroad till December 31, 2018. Besides, all the references referred in those literatures including primary ones and literature reviews were also searched. Two researchers were responsible to screen literatures in accordance with the inclusive an...