Adverse drug events as a cause of hospital admission in the elderly

Background: Previous studies of adverse drug events (ADE) as a cause of hos pital admission in the elderly have often been limited in their ability to assess fully the impact and potential for prevention because they either di d not include all categories of ADE and/or did not assess severity and prev entability. Aims: To assess the frequency, severity and preventability of ADE causing e mergency medical admissions in the elderly. Methods: Cross-sectional survey of 219 patients aged 75 years and over who were consecutive unplanned admissions to acute medical units of the Royal H obart Hospital in an 8-week period during August and September 1998. Results: Seventy-three of 240 (30.4%) admissions may have been a result of ADE. Patients admitted because of ADE were taking more drugs than those adm itted for other reasons. Most ADE were adverse drug reactions to a single ( 46%) or multiple drugs (25%). Non-compliance, omission or cessation of indi cated treatment accounted collectively for 26% of admissions. Of all ADE ad missions 53.4% were considered definitely preventable. The commonest causat ive drugs were cardiovascular drugs (48.4%), and the commonest manifestatio ns were falls and postural hypotension (24.1%), heart failure (16.9%) and d elirium (14.5%). ADE categories in which a high proportion of admissions wa s both severe and definitely preventable were non-compliance and omission o f indicated treatment. Conclusions: Adverse drug events are a common preventable cause of unplanne d medical admissions in the elderly. Non-compliance and omission of indicat ed treatment are causes of ADE-related admissions that are both preventable and frequently associated with severe ADE.