Preventive Effects of Melatonin on Delirium in Intensive Care Unit Patients: A Meta-Analysis of Randomized Controlled Trials.

AIMS: To investigate the preventive efficacy of melatonin on the incidence of delirium and other clinical outcomes of subjects in the intensive care unit (ICU).

METHODS: Randomized controlled trials concerning the effects of melatonin on delirium published from inception to July 2022 were identified from PubMed, Embase, and the Cochrane Library. The primary outcome was delirium incidence. The secondary outcome was the length of ICU stay, the duration of mechanical ventilation, and the mortality in ICU. A meta-analysis was performed. Estimates were presented as risk ratio (RR) or standard mean difference (SMD) with 95% confidence interval (CI).

RESULTS: Eleven RCTs with 2002 patients were included. The forest plots showed that the delirium incidence did not significantly decrease after melatonin administration (RR 0.85; 95% CI, 0.61~1.18, P = .32, I2=60%, P for heterogeneity = .01). The subgroup analyses confirmed that melatonin significantly reduced the incidence of delirium (RR 0.70; 95% CI, 0.56~0.89, P = .003, I2 = 32%, P for heterogeneity = .22) for the special ICU patients. Also, for ICU patients, the length of ICU stays, duration of mechanical ventilation, and mortality were not significantly decreased after melatonin treatment (all P > .05).

CONCLUSION: Melatonin may decrease the incidence of delirium for special ICU patients. PROSPERO registration number: CRD42022354874.