Background Computerised provider order entry (CPOE) systems are widely used in clinical settings for the electronic ordering of medications, laboratory tests and radiological therapies. However, evidence regarding effects of CPOE-based medication ordering on clinical and safety outcomes is mixed. We conducted an overview of systematic reviews (SRs) to characterise the cumulative effects of CPOE use for medication ordering in clinical settings.

Methods MEDLINE, EMBASE, CINAHL and the Cochrane Library were searched to identify published SRs from inception to 12 February 2018. SRs investigating the effects of the use of CPOE for medication ordering were included. Two reviewers independently extracted data and assessed the methodological quality of included SRs.

Results Seven SRs covering 118 primary studies were included for review. Pooled studies from the SRs in inpatient settings showed that CPOE use resulted in statistically significant decreases in medication errors and adverse drug events (ADEs); however, there was considerable variation in the magnitude of their relative risk reduction (54%–92% for errors, 35%–53% for ADEs). There was no significant relative risk reduction on hospital mortality or length of stay. Bibliographic analysis showed limited overlap (24%) among studies included across all SRs.

Conclusion SRs on CPOEs included predominantly non-randomised controlled trials and observational studies with varying foci. SRs predominantly focused on inpatient settings and often lacked comparison groups; SRs used inconsistent definitions of outcomes, lacked descriptions regarding the effects on patient harm and did not differentiate among the levels of available decision support. With five of the seven SRs having low to moderate quality, findings from the SRs must be interpreted with caution. We discuss potential directions for future primary studies and SRs of CPOE.