Twelve observational studies were included: three prospective cohort studies, eight retrospective cohort studies and one controlled cross-sectional study. Four studies were on adults in intensive care units. Eight were paediatric studies (four in intensive care unit settings and three on paediatric wards). Sample sizes were not reported.
Use of computerised physician order entry systems was associated with a statistically significant reduction in medication prescription errors (RR 0.08, 95% CI 0.01 to 0.77, I2=34%; three studies). Although there was some reduction in potential or actual adverse drug events this was not statistically significant and there was considerable heterogeneity (I2=65%, three studies). Overall there was no effect on mortality (heterogeneity reported as I2=0%, four studies); one study reported a statistically significant increase in mortality.
Use of computerised physician order entry systems in adult intensive care unit settings was associated with an increase in medical prescription errors in the initial implementation period in one study and a clinically beneficial effect in three studies.
In paediatric settings, five studies reported on medical prescription errors or adverse drug events. Use of computerised physician order entry systems were associated with a statistically significant benefit in three studies and a statistically non-significant benefit in one study; in one study overall results were beneficial, but there was an increase in potential adverse drug events. Three studies reported on mortality: one reported an increase with use of computerised physician order entry systems; one reported a decrease; and one reported a statistically non-significant decrease.