Effect of melatonin versus placebo for prevention of delirium among medically hospitalised patients: study protocol for a single-centre, double-blinded, randomised controlled trial (project RESTORE).

introductionDelirium, a common neuropsychiatric condition in hospitalised older adults, is associated with increased mortality, longer hospital stays and cognitive decline. The potential of melatonin to prevent delirium by improving sleep patterns and regulating circadian rhythms is promising, though existing evidence is mixed. This study aims to evaluate the efficacy of melatonin in preventing delirium in medically hospitalised patients aged 65 years and older. METHODS AND ANALYSIS: This randomised, double-blind, placebo-controlled trial will enrol 240 patients aged 65 or older admitted to general medical wards at Sultan Qaboos University Hospital starting from September 2024. Participants will be randomly assigned to receive either 5 mg or 8 mg of melatonin or a placebo nightly for up to 5 days. The primary outcome is the incidence of delirium, assessed using the 3 min Diagnostic Confusion Assessment Method during the first 5 days. Secondary outcomes include the duration of delirium, sleep patterns and other clinical measures, such as hospital length of stay and 28-day readmission. ETHICS AND DISSEMINATION: The study protocol has received ethical approval from the Medical Research Ethics Committee at Sultan Qaboos University (REF. NO. SQU-EC/024\2024, MREC #3240). All participants or their legal proxies will provide informed consent prior to enrolment. Results will be disseminated through peer-reviewed publications and conference presentations, contributing to the global evidence base on delirium prevention strategies in hospitalised older adults. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov under the identifier NCT06509191.