Potentially inappropriate drug prescribing among first-visit elderly outpatients in Taiwan.

STUDY OBJECTIVE: To determine the prevalence and risk factors of potentially inappropriate drug prescribing among first-visit elderly outpatients.

DESIGN: Cross-sectional survey.

SETTING: An urban 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.

MEASUREMENTS AND MAIN RESULTS: Potentially inappropriate drug prescribing was assessed according to updated Beers criteria. Ninety-seven potentially inappropriate drugs were identified in 93 (10.5%) patients. The most common classes were sedative-hypnotics (18.6%) and muscle relaxants (17.5%). Twenty (20.6%) of these inappropriate drugs had a high severity potential according to the Beers criteria. Patients prescribed potentially inappropriate drugs were more likely to be prescribed several drugs versus those who were not prescribed potentially inappropriate drugs (4.0+/-1.9 vs 2.8+/-1.4, p<0.001). Multiple logistic regression analysis revealed an interaction between age and the number of prescribed drugs on the risk of having potentially inappropriate drugs prescribed. In patients who were prescribed four agents or less, the risk was not associated with increasing age; in those who were prescribed five drugs or more, the risk was positively associated with increasing age.

CONCLUSION: Potentially inappropriate drug prescribing among first-visit elderly outpatients was relatively low. Increasing patient age combined with increased number of drugs prescribed was associated with increased risk of having potentially inappropriate drugs prescribed.