INCIDENCE OF ADVERSE DRUG EVENTS AND POTENTIAL ADVERSE DRUG EVENTS - IMPLICATIONS FOR PREVENTION

Objectives.-To assess incidence and preventability of adverse drug eve nts (ADEs) and potential ADEs. To analyze preventable events to develo p prevention strategies. Design.-Prospective cohort study. Participant s.-All 4031 adult admissions to a stratified random sample of 11 medic al and surgical units in two tertiary care hospitals over a 6-month pe riod. Units included two medical and three surgical intensive care uni ts and four medical and two surgical general care units. Main Outcome Measures.-Adverse drug events and potential ADEs. Methods.-Incidents w ere detected by stimulated self-report by nurses and pharmacists and b y daily review of all charts by nurse investigators. Incidents were su bsequently classified by two independent reviewers as to whether they represented ADEs or potential ADEs and as to severity and preventabili ty. Results.-Over 6 months, 247 ADEs and 194 potential ADEs were ident ified. Extrapolated event rates were 6.5 ADEs and 5.5 potential ADEs p er 100 nonobstetrical admissions, for mean numbers per hospital per ye ar of approximately 1900 ADEs and 1600 potential ADEs. Of all ADEs, 1% were fatal (none preventable), 12% life-threatening, 30% serious, and 57% significant. Twenty-eight percent were judged preventable. Of the life-threatening and serious ADEs, 42% were preventable, compared wit h 18% of significant ADEs, Errors resulting in preventable ADEs occurr ed most often at the stages of ordering (56%) and administration (34%) ; transcription (6%) and dispensing errors (4%) were less common. Erro rs were much more likely to be intercepted if the error occurred earli er in the process: 48% at the ordering stage vs 0% at the administrati on stage, Conclusion.-Adverse drug events were common and often preven table; serious ADEs were more likely to be preventable. Most resulted from errors at the ordering stage, but many also occurred at the admin istration stage. Prevention strategies should target both stages of th e drug delivery process.