The epidemiology of preventable adverse drug events: a review of the literature.

BACKGROUND: A growing amount of data suggests that adverse drug events (ADEs) in hospital settings are frequent and result in substantial harm. Even though prevention is where efforts must be directed, only a few studies have reported on the preventability of these events. The objective of this article is to review the literature of ADEs and their preventability, and to report on their incidences, characteristics, risk factors, costs and prevention strategies.

METHODS: We systematically searched Medline and Embase for literature published between 1980 and June 2002. All articles reporting primary data on the incidences of ADEs and their preventability in hospital settings were included.

RESULTS: In the 8 articles retrieved the incidences of ADEs were between 0.7% and 6.5% of hospitalized patients; in up to 56.6% these events were judged to be preventable. Furthermore, ADEs accounted for 2.4% to 4.1% of admissions to inpatient facilities; preventability was stated in up to 69.0% of these events. A substantial body of preventable ADEs, the so-called medication errors, occur in the process of ordering, transcribing, dispensing and administrating the drugs. Further investigations into medication errors at the ordering stage reveal their occurrence in up to 57.0 per 1,000 orders. Between 18.7% and 57.7% of those errors have the potential for harm, but only in about 1% they result in preventable ADEs.

IMPLICATIONS: The detection of errors having only the potential for harm by means of computerized surveillance has shown to be a useful technique in order to understand and prevent ADEs. Apart from the use of sophisticated computer techniques the participation of pharmacists in the drug prescribing process results in a tremendous error reduction. The greatest task in changing the health care system into a system with safety as its first priority is to create a culture of constant learning from mistakes among health care professionals. The appreciation of the health care teams' ideas and perceptions for improvement, and their implementation through small improvement cycles, may represent the leading strength in error reduction and health care improvement.