title: Incidence and preventability of adverse drug events in nursing homes.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Meyers Primary Care Institute, the Fallon Healthcare System, and the University of Massachusetts Medical School (JHG, TSF, DM, SJ, ME, MB), Worcester, Massachusetts, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Gurwitz
authors.forename: T S
authors.initials: TS
authors.lastname: Field
authors.forename: J
authors.initials: J
authors.lastname: Avorn
authors.forename: D
authors.initials: D
authors.lastname: McCormick
authors.forename: S
authors.initials: S
authors.lastname: Jain
authors.forename: M
authors.initials: M
authors.lastname: Eckler
authors.forename: M
authors.initials: M
authors.lastname: Benser
authors.forename: A C
authors.initials: AC
authors.lastname: Edmondson
authors.forename: D W
authors.initials: DW
authors.lastname: Bates
mesh_terms: D000058:Accidental Falls; D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects; D001803:Blood Transfusion; D016009:Chi-Square Distribution; D015331:Cohort Studies; D003243:Consciousness / Q000187:drug effects; D003693:Delirium / Q000139:chemically induced; D016903:Drug Monitoring; D011307:Drug Prescriptions; D064420:Drug-Related Side Effects and Adverse Reactions; D005076:Exanthema / Q000139:chemically induced; D050723:Fractures, Bone / Q000209:etiology; D006470:Hemorrhage / Q000139:chemically induced; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D008134:Long-Term Care; D008404:Massachusetts; D008499:Medical Records; D009735:Nursing Homes; D011315:Preventive Medicine; D011619:Psychotropic Drugs / Q000009:adverse effects; D012720:Severity of Illness Index; D014581:Urticaria / Q000139:chemically induced
chemical_list: D000925:Anticoagulants; D011619:Psychotropic Drugs