The effect of melatonin on delirium in hospitalised patients: A systematic review and meta-analyses with trial sequential analysis

Melatonin is an endogenous hormone, which regulates circadian rhythms and promotes sleep. In recent years, several randomised controlled trials examining the prophylactic use of melatonin to prevent delirium were published with conflicting findings. The primary aim of this review was to determine the effect of melatonin on the incidence of delirium in hospitalised patients. MEDLINE, EMBASE and CENTRAL were systematically searched from their inception until December 2018. All randomised clinical trials were included. Sixteen trials (1634 patients) were included in this meta-analysis. Incidence of delirium was not significantly lower in patients who received melatonin, with an odd ratio, OR (95%Cl) of 0.55 (0.24–1.26); ρ = 0.16, certainty of evidence = low, trial sequential analysis = inconclusive. However, patients who randomised to melatonin had a significantly shorter length of stay in intensive care units, with a mean difference, MD (95%CI) of −1.84 days (−2.46, −1.21); ρ