Melatonin lowers risk of postoperative delirium

For adults undergoing surgery, melatonin appears to help reduce the likelihood of postoperative delirium, according to the results of a meta-analysis.

Researchers searched multiple online databases for studies in which the effect of melatonin in preventing postoperative delirium in adults was examined. The Cochrane risk of bias 2 tool was used to assess the risk of bias.

The primary outcome was the incidence of postoperative delirium. Secondary outcomes included the duration of postoperative delirium and length of hospital stay. Data were synthesized using a random-effects meta-analysis and presented using forest plots.

A total of 11 studies, with 1,244 participants overall, were included in the meta-analysis. Seven of these studies used melatonin in variable doses, and four used ramelteon. There were eight different diagnostic tools used to diagnose postoperative delirium. Time points for assessment also varied.

Pooled data showed that compared with control, melatonin was associated with 59-percent reduced odds of developing postoperative delirium (odds ratio, 0.41, 95 percent confidence interval, 0.21–0.80; p=0.01).

Of the studies included, six were deemed to have low risk of bias.

Despite the positive results of the meta-analysis, the included studies showed some inconsistency in their methodology and outcome reporting. More research is needed to determine the optimum regimen for melatonin administration, along with consensus of how best to evaluate results.