PMH27 - Age Disparities in Off-Label Use of Antipsychotics Among Wa Medicare-D Beneficiaries

Abstract

Medicare, which covers all adults over age 65 and younger adults with work disabilities, is the largest public health insurance program in the US. Program drug costs have risen dramatically in the past two decades, due in part to a jump in prescribing of psychiatric medications. This study analyzes patterns of antipsychotic use among Washington state Medicare beneficiaries in 2013. We used Medicare claims data to ascertain the program enrollment status of Medicare beneficiaries, omitting decedents and beneficiaries who added or dropped drug coverage during the 12 month observation period. Our preliminary study sample consisted of all living WA adults (over age 21) continuously enrolled in Medicare Part D or Medicare Advantage in 2013 (N=614,632). We then used the Part D Drug Event file to identify beneficiaries within this subgroup who filled one or more antipsychotic prescriptions (N=39,541). About 6.4% of WA residents continuously enrolled in Medicare Part D or Medicare Advantage received one or more antipsychotic prescriptions. Younger Medicare beneficiaries (aged 21-64) were prescribed antipsychotics at nearly six times the rate of those over age 65 or older (20.0% vs. 3.4%). The majority of antipsychotic users (51.2%) did not appear to have an FDA indicated diagnosis of schizophrenia, major depression, or bipolar and manic disorders. Use for nonindicated diagnoses was more common in older age groups. For example, 84% of antipsychotic users over age 75 do not have an indicated diagnosis, but 51.9% have Alzheimer’s or another dementia. Most WA Medicare beneficiaries who use antipsychotics are under age 65. This group receives early Medicare coverage because they are unable to work due to a disabling health condition, and psychiatric conditions are a very common cause of work disability. Consequently, most younger beneficiaries use antipsychotics for indicated diagnoses.