CRD Summary: The review concluded that adjunctive low-dose haloperidol prophylaxis reduced severity and duration of delirium and length of hospital stay in elderly at-risk patients. Further research needed to determine: an optimal pharmacological approach; combination with non-pharmacological strategies; and generalisability. The paucity of evidence and methodological uncertainties made the authors' conclusion seem overstated and it may not be reliable.

CRD Commentary: Three databases were searched. It was not known whether the search was restricted by language. No attempts were made to locate unpublished papers. It is possible that relevant studies were missed and language and publication biases could not be ruled out. The authors did not report the methods used to select papers, extract data or assess study quality, therefore, the likelihood of reviewer error and bias at these stages could not be assessed. A descriptive summary of the included study was presented and results tabulated.

The authors highlighted a number of limitations: that the study was underpowered to detect an effect on the primary outcome (incidence of delirium); that it was not clear whether the difference found on the DSR-R-98 represented a clinically meaningful difference; and that it was not clear whether results could be applied to non-orthopaedic surgical patients, non-surgical patients, or those with neurologic comorbidities.

Given the paucity of the evidence found and the uncertainties in the research process, the authors' conclusions based on the secondary outcomes of a single RCT seemed overstated and may not be reliable.