Regional surveillance of emergency-department visits for outpatient adverse drug events.

AIMS: To determine the (1) incidence of adverse drug events (ADEs) in 10 emergency department (EDs) of general hospitals in the Regione Campania (southern Italy), (2) rate of ADE-related hospital admissions, (3) drug classes most frequently involved, and (4) the types of ADEs and their frequency.
METHODS: We performed a cohort study of all patients attending the EDs. This study was carried out in two observational periods of 10 days each in 10 EDs. Demographic, clinical, and pharmacological data about all patients admitted to EDs were collected by trained and qualified monitors. Records related to ADEs were analyzed and validated by a specific scientific committee.
RESULTS: Of 7,861 ED visits, 96 were ADE-related. The incidence of hospitalization was higher in patients who had taken medication than in patients with a negative drug history (24.9 vs. 16.4%). ADEs were significantly more frequent in women. Patients aged between 60 and 69 years and between 30 and 39 years were significantly more likely to experience an ADE. Serious ADEs were identified in 20 ED visits (20.8% of total sample). Antibiotics, NSAIDs, and agents acting on the renin-angiotensin system were the drugs most often involved in ADEs. In multivariate analyses, the adjusted odds ratio was 3.4 (95% CI: 1.07-2.84) for patients taking NSAIDs, 4.78 (95% CI: 2.26-10.12) for those taking beta(2)-adrenergic-receptor agonists, and 6.20 (95%CI: 2.74-14.06) for those taking beta-lactam antibiotics.
CONCLUSION: This study shows that ADEs are an important problem in industrialized countries. Moreover, it shows that ADEs affect hospital admission rates and reinforces the importance of drug-induced disease as a public health problem.