Incidence and Preventability of Medication Errors and ADEs in Ambulatory Care Older Patients

To assess the incidence of medication errors, adverse drug events (ADEs), and potential ADEs (poADEs) in patients 65 years of age and older.

This is a retrospective cohort study (2011 to 2014).

The study was performed at a section 330 federally funded ambulatory health care center.

The study was a convenience sample selected in a nonrandomized way from event reports filed in those years.

Data were collected through event reports and medical record review. Descriptive statistics and chi-square were employed to analyze data.

During the study period, at least one medication error, poADE, or ADE report was documented in 170 out of 2,218 older patients (incidence: 12.5, 9.4, and 5.0 per 100 patient-years, respectively); 42.9% of ADEs were preventable. The chronic conditions most frequently related to ADEs were diabetes (18%), hypertension (18%), and hyperlipidemia (12%). The use of hypoglycemic agents was commonly associated with ADEs (14%; P = 0.001). An increased number of prescribed medications were significantly associated with all the adverse events.

Medication errors, poADEs, and ADEs are common in patients 65 years of age or older taking more than three medications. Almost half of the detected ADEs were preventable.