Adverse drug events, especially those that may have been preventable, are among the
most serious concerns about medication use in nursing homes. We studied the incidence
and preventability of adverse drug events and potential adverse drug events in nursing
homes.
We performed a cohort study of all long-term care residents of 18 community-based
nursing homes in Massachusetts during a 12-month observation period. Potential drug-related
incidents were detected by stimulated self-report by nursing home staff and by periodic
review of the records of nursing home residents by trained nurse and pharmacist investigators.
Each incident was classified by 2 independent physician-reviewers, using a structured
implicit review process, by whether or not it constituted an adverse drug event or
potential adverse drug event (those that may have caused harm, but did not because
of chance or because they were detected), by the severity of the event (significant,
serious, life-threatening, or fatal), and by whether it was preventable. Examples
of significant events included nonurticarial rashes, falls without associated fracture,
hemorrhage not requiring transfusion or hospitalization, and oversedation; examples
of serious events included urticaria, falls with fracture, hemorrhage requiring transfusion
or hospitalization, and delirium.
During 28,839 nursing home resident-months of observation in the 18 participating
nursing homes, 546 adverse drug events (1.89 per 100 resident-months) and 188 potential
adverse drug events (0.65 per 100 resident-months) were identified. Of the adverse
drug events, 1 was fatal, 31 (6%) were life-threatening, 206 (38%) were serious, and
308 (56%) were significant. Overall, 51% of the adverse drug events were judged to
be preventable, including 171 (72%) of the 238 fatal, life-threatening, or serious
events and 105 (34%) of the 308 significant events (P < 0.001). Errors resulting in
preventable adverse drug events occurred most often at the stages of ordering and
monitoring; errors in transcription, dispensing, and administration were less commonly
identified. Psychoactive medications (antipsychotics, antidepressants, and sedatives/hypnotics)
and anticoagulants were the most common medications associated with preventable adverse
drug events. Neuropsychiatric events were the most common types of preventable adverse
drug events.
Adverse drug events are common and often preventable in nursing homes. More serious
adverse drug events are more likely to be preventable. Prevention strategies should
target the ordering and monitoring stages of pharmaceutical care.