Predictors of medication errors among elderly hospitalized patients.

Medication errors are a serious safety concern and most errors are preventable. A retrospective study design was employed to describe medication errors experienced during 10187 hospitalizations of elderly patients admitted to a Midwest teaching hospital between July 1, 1998 and December 31, 2001 and to determine the factors predictive of medication errors. The model considered patient characteristics, clinical conditions, interventions, and nursing unit characteristics. The dependent variable, medication error, was measured using a voluntary incident reporting system. There were 861 medication errors; 96% may have been preventable. Most errors were omissions errors (48.8%) and the source was administration (54%) or transcription errors (38%). Variables associated with a medication error included unique number of medications (polypharmacy), patient gender and race, RN staffing changes, medical and nursing interventions, and specific pharmacological agents. Further validation of this explanatory model and focused interventions may help decrease the incidence of medication errors.