Adverse drug reactions in a population of hospitalized very elderly patients

Abstract

Objectives: The aims of the study were to determine the rates, types, severity and preventability of adverse drug reactions (ADRs) in a hospitalized population of very elderly patients (over 80 years of age) and to identify factors that predispose the very elderly to an ADR.

Methods: An observational study was conducted in patients over 80 years of age admitted to four care of the elderly wards in Brighton and Sussex University Hospitals NHS Trust. The main outcome measures were the incidence of ADRs during inpatient stay in older patients and the identification of the major drug classes involved and the risk factors contributing to the occurrence of ADRs.

Results: A total of 560 very elderly patients were recruited, 74 of whom experienced one or more ADR (83 in total), representing an incidence of 13.2% (95% CI 10.4, 16). Sixty-three percent of all ADRs were considered preventable, with 57 classified as serious and three as life threatening. The drug classes frequently implicated in ADRs were cardiovascular agents (34%), analgesic medications (18%) and anti-diabetic drugs (10%). Five variables were established as independent predictors of ADRs: number of medications, use of hypoglycaemic agents, history of hyperlipidaemia, raised white cell count on admission, and length of stay.

Conclusions: The ADR incidence reported in this population was no greater than that seen in other studies for both general medical patients and those elderly patients over 65 years of age. A significant proportion of ADRs were preventable, and this suggests that closer monitoring of high-risk elderly patients is needed to address this problem.