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Adverse drug events in the outpatient setting: an 11‐year national analysis
Author(s) -
Bourgeois Florence T.,
Shan Michael W.,
Valim Clarissa,
Mandl Kenneth D.
Publication year - 2010
Publication title -
pharmacoepidemiology and drug safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.023
H-Index - 96
eISSN - 1099-1557
pISSN - 1053-8569
DOI - 10.1002/pds.1984
Subject(s) - medicine , emergency department , polypharmacy , emergency medicine , ambulatory care , population , multivariate analysis , health care , outpatient visits , outpatient clinic , pharmacoepidemiology , adverse effect , pediatrics , medical emergency , medical prescription , environmental health , psychiatry , economics , economic growth , pharmacology
Purpose Adverse drug events (ADEs) are a common complication of medical care resulting in high morbidity and medical expenditure. Population level estimates of outpatient ADEs are limited. Our objective was to provide national estimates and characterizations of outpatient ADEs and determine risk factors associated with these events. Methods Data are from the National Center for Health Statistics which collects information on patient visits to outpatient clinics and emergency departments throughout the United States. We examined visits between 1995 and 2005 and measured the national annual estimates of and risk factors for outpatient ADEs requiring medical treatment. Results The national annual number of ADE‐related visits was 4 335 990 (95%CI: 4 326 872–4 345 108). Visits for ADEs to outpatient clinics increased over the study period from 9.0 to 17.0 per 1000 persons ( p ‐value for trend < 0.001). In multivariate analyses, factors associated with ADE visits included patient age (OR: 2.13; 95%CI: 1.63–2.79 for 65 years and older), number of medications taken by patient (OR: 1.88; 95%CI: 1.58–2.25 for five medications or more), and female gender (OR: 1.51; 95%CI: 1.34–1.71). Overall, outpatient ADEs resulted in 107 468 (95%CI: 89 011–125 925) hospital admissions annually, with older patients at highest risk for hospitalization ( p ‐value for trend < 0.001). Conclusions Both patient age and polypharmacy use are risk factors for ADE‐related healthcare visits, which have substantially increased in outpatient clinics between 1995 and 2005. The incidence of ADEs has particularly increased among patients 65 years and older with as many as 1 in 20 persons seeking medical care for an ADE. Copyright © 2010 John Wiley & Sons, Ltd.