Results from a double blinded, randomised, placebo-controlled, feasibility trial of melatonin for the treatment of delirium in older medical inpatients.

Abstract

Delirium is common in elderly inpatients, causing distress, cognitive decline and death. No known intervention improves the course of delirium; current treatments are symptomatic, and limited by lack of efficacy and adverse effects. There is an urgent need to find an effective treatment for delirium. To determine the feasibility of a trial of oral melatonin 5 mg nightly for five nights for the treatment of delirium in older medical inpatients, and determine the participants required to demonstrate a clinically and statistically significant decrease in severity of delirium in older medical inpatients treated with melatonin. This was a double blinded, randomised controlled trial in general internal medicine units of a tertiary teaching hospital. Older (≥70 years) inpatients with confusion assessment method positive hyperactive or mixed delirium were suitable for inclusion. Subjects received melatonin 5 mg oral nightly for five nights or matching placebo. The primary outcome was the Memorial Delirium Assessment Scale (MDAS) administered daily. No adverse effects occurred due to melatonin. In the treatment group, the mean change in MDAS from baseline during treatment period was 2.5 ± 5.0 points, in the placebo group, 2.1 ± 4.1 points, a non-significant difference. A power calculation accounting for drop-out (31.0%), suggests 120 participants would be required to demonstrate with 90% power that melatonin 5 mg reduces the severity of delirium by 3 points or more on MDAS. A trial of the hypothesis that 5 mg melatonin nightly for five nights reduces delirium severity in older medical inpatients would require 120 patients, and is feasible.