Objective: Computerized provider order entry (CPOE) has been shown to improve patient safety by reducing medication errors and subsequent adverse drug events (ADEs). Studies demonstrating these benefits have been conducted primarily in the inpatient setting, with fewer in the ambulatory setting. The objective was to evaluate the effect of a basic, ambulatory CPOE system on medication errors and associated ADEs.
Design: This quasiexperimental, pretest-post-test study was conducted in a community-based, multispecialty health system not affiliated with an academic medical center. The intervention was a basic CPOE system with limited clinical decision support capabilities.
Measurement: Comparison of prescriptions written before (n=5016 handwritten) to after (n=5153 electronically prescribed) implementation of the CPOE system. The primary outcome was the occurrence of error(s); secondary outcomes were types and severity of errors.
Results: Frequency of errors declined from 18.2% to 8.2%-a reduction in adjusted odds of 70% (OR: 0.30; 95% CI 0.23 to 0.40). The largest reductions were seen in adjusted odds of errors of illegibility (97%), use of inappropriate abbreviations (94%) and missing information (85%). There was a 57% reduction in adjusted odds of errors that did not cause harm (potential ADEs) (OR 0.43; 95% CI 0.38 to 0.49). The reduction in the number of errors that caused harm (preventable ADEs) was not statistically significant, perhaps due to few errors in this category.
Conclusions: A basic CPOE system in a community setting was associated with a significant reduction in medication errors of most types and severity levels.