Background: We sought to determine the extent of potentially inappropriate outpatient prescribing for elderly patients, as defined by the Beers revised list of drugs to be avoided in elderly populations.
Methods: We conducted a retrospective cohort study using the outpatient prescription claims database of a large, national pharmaceutical benefit manager. The cohort included 765,423 subjects 65 years or older, who were covered by a pharmaceutical benefit manager and filed 1 or more prescription drug claims during 1999. Main outcome measures were the proportion of subjects who filled a prescription for 1 or more drugs of concern and the proportion of subjects who filled prescriptions for 2 or more of the drugs.
Results: A total of 162,370 subjects (21%) filled a prescription for 1 or more drugs of concern. Amitriptyline and doxepin accounted for 23% of all claims for Beers list drugs, and 51% of those claims were for drugs with the potential for severe adverse effects. More than 15% of subjects filled prescriptions for 2 drugs of concern, and 4% filled prescriptions for 3 or more of the drugs within the same year. The most commonly prescribed classes were psychotropic drugs and neuromuscular agents.
Conclusions: The common use of potentially inappropriate drugs should serve as a reminder to monitor their use closely. Pharmaceutical claims databases can be important tools for accomplishing this task, though clinical and laboratory data are needed to improve the sensitivity and specificity of patient-specific alerts.