A literature search performed in October 2007 identified studies evaluating the effect of CPOE on prescribing errors. Due to the variation in definitions and terms applied by researchers we used a broad search strategy which incorporated studies of medication errors as well as prescribing errors in hospitalized patients. The search strategy and terms applied to the electronic databases are outlined in Figure 4 (available as an online data supplement at http://www.jamia.org
We searched Ovid MEDLINE (1950–2007); CINAHL (Nursing and Allied Health) (1982–2007); EMBASE (1974–2007); Journals@Ovid, Inspec via Ovid (1969–2007); International Pharmaceutical Abstract Series via Ovid (1970–2007); Cochrane Database of Systematic Reviews (third Quarter 2007); and the Cochrane Central Register of Controlled Trials (third Quarter 2007). This yielded 954 articles. Additional citations were sourced from reference lists of journal and review articles (n = 45) and a manual search of the Journal of the American Medical Informatics Association (1994–2007; 82 issues) (n = 8) (). After initial screening of titles and abstracts, 71 articles were considered for full text review. Review articles, implementation guidelines, user-satisfaction surveys, opinions and letters were excluded. Studies in which the full text was unobtainable (n = 1) were also excluded and searches were limited to articles published in English. Studies that did not include a sample size to allow error rate calculation were also excluded.
Flow chart showing search outcome.
Two clinical pharmacist reviewers extracted all the data and independently appraised all 71 studies. Disagreement was resolved by discussion and consensus. Studies were evaluated and included only if they reported original data from a study which was conducted in a hospital inpatient setting, if the study design was a pre- and post-CPOE implementation or a comparative (handwritten and CPOE) study, and if one of the main outcome measures was prescribing error rates. Eleven articles met all of these inclusion criteria. 22–32
In addition, two studies which measured the impact of CPOE on medication errors in hospitalized patients 21,36
contained sufficient detail to extract the prescribing error results so they were also included. Thus, 13 articles were included in our review.
Of the 58 excluded studies, four were review articles. Four studies were not conducted in an inpatient setting (one was set in each of an outpatient, emergency, or community setting, and one focused on discharge medications). Eighteen studies focused on medication safety in hospital inpatients (12 of which measured the impact of CPOE on medication safety, but none of these included prescribing errors). Twelve studies evaluated various CPOE-related outcomes other than medication errors or prescribing errors. Four CPOE-related discussion papers did not measure any health care variables. The full text of one article could not be located for review, but its title and abstract suggested that it would not have been selected for inclusion. A further ten studies measured the impact of CPOE on medication errors in hospitalized patients. One study was excluded because a sample size was not given. Nine studies were excluded because the prescribing error details were insufficient. Five CPOE-related studies focused on prescribing errors in hospitalized patients were excluded because three were not pre-post CPOE studies or comparative handwritten and CPOE studies, one was not a CPOE study, and one was a case study analysis of prescribing errors. Details of excluded studies may be obtained from the authors.
We separately examined studies of adult patients in ICU and general wards, and pediatric inpatients, as prescribing practices may be different in these settings. Prescribing for pediatric patients involves selection of a medication and its dose, frequency, and formulation, pharmacokinetically and pharmacodynamically suitable for a combination of factors including age, weight or body surface area, and clinical condition. 45
The prescriber may need to adjust medication doses according to changes in the patient's body weight. 3
Furthermore, for some “off-label” indications there is often only limited dosing information available. These factors increase the risk of errors, particularly dosing errors. 3,45
In addition, errors involving the intravenous (IV) route and certain classes of drugs, including anti-infectives, fluids and electrolytes, analgesics and sedatives, have been associated with more frequent prescribing errors in pediatric patients. 3
Similarly, a prescribing error of chemotherapy can have potentially catastrophic consequences due to the high toxicity and narrow therapeutic index of this class of drugs. 46
In analyzing the included papers, we focused on changes in error rates and severity, and evidence of any new types of errors generated. We were also cognizant of international differences in prescribing practices. In the UK and Australia, it is practice that a clinician will prescribe medication on the drug chart which will then become the medication administration record (MAR). This process differs in the United States and in Europe, where the clinician will initially prescribe medications, on a “doctor's order sheet” in the United States, or in the patient's medical notes in Europe. Various health professionals are then involved in transcription of the clinician's original order to the MAR. These differences in prescribing practices are a likely source of variation in the frequency and causes of error reported in medication error studies. 45
We excluded transcription errors from our definition of prescribing errors, and considered transcription errors to fall under the wider umbrella of medication errors. These types of errors were excluded from this literature review.