Use of the beers criteria to predict adverse drug reactions among first-visit elderly outpatients

Study Objective. To determine whether the Beers criteria can predict adverse drug reactions (ADRs) in first-visit elderly outpatients. Design. Prospective cohort study. Setting. Outpatient clinics of a tertiary care and academic medical center in southern Taiwan. Patients. Eight hundred eighty-two patients aged 65 years or older who were prescribed drugs at their first visit to either the medical center's outpatient internal medicine clinic or family medicine clinic between March 1, 2001, and July 31, 2001. Intervention. Telephone survey conducted 1 week after clinic visit. Measurements and Main Results. Potentially inappropriate drugs were assessed by the updated Beers criteria. Adverse drug reactions were detected by telephone survey and evaluated by the Naranjo criteria 1 week after drug administration. Of the 550 respondents, 64 (11.6%) had potentially inappropriate drugs prescribed and 126 (22.9%) had ADRs. Multiple logistic regression analysis revealed associations between ADRs and potentially inappropriate drug prescribing (relative risk [RR] 15.3, 95% confidence interval [CI] 4.0-58.8), number of prescribed drugs (RR 1.3, 95% CI 1.1-1.5), history of ADRs (RR 2.1, 95% CI 1.3-3.4), and noncompliance with prescribed drugs (RR 2.0, 95% CI 1.1-3.7). In patients who had potentially inappropriate drugs prescribed, the number of prescribed drugs was not significantly associated with ADRs (RR 0.8, 95% CI 0.6-1.1). In patients who did not have potentially inappropriate drugs prescribed, more prescribed drugs increased the risk of ADRs (RR 1.3, 95% CI 1.1-1.5). Conclusion. A positive association exists between potentially inappropriate drug prescribing, as defined by the Beers criteria, and ADRs in first-visit elderly outpatients. Clinicians should be alert to the possibility of ADRs if a patient takes more than five drugs, has a history of ADRs, or exhibits poor compliance with prescribed drugs.