Examination of multiple medication use among TRICARE beneficiaries aged 65 years and older.

BACKGROUND: The simultaneous use of multiple prescription medications has been associated with an increased risk of adverse drug events and other drug-related complications, especially in the elderly. OBJECTIVE: To quantify the prevalence of use of multiple medications among a sample of Department of Defense (DoD) health care beneficiaries, aged 65 years and older, who used their TRICARE (military health care services) benefit to obtain prescription medication. METHODS: Outpatient pharmacy fill records were analyzed for a 10% random sample of 1.27 million TRICARE beneficiaries aged 65 years and older who obtained 1 or more prescription medications in the 90-day period from December 1, 2004, through February 28, 2005. The First DataBank generic code number was used to identify drugs and to calculate the mean number of medications obtained and the mean, frequency, and type of American Hospital Formulary System drug therapy categories. Statistical significance for gender and age subgroups was tested via inde...