Insurance claim study tracks timing of shift to polypharmacy antipsychotic medications rarely used at home.

SAN DIEGO — Polypharmacy is common among patients taking antipsychotic medications, but it is fairly unusual for patients to be initiated on multiple drugs, so how long does it take to progress from monotherapy to polypharmacy?

A study based on commercial insurance and Medicare Part D claim forms found that adults move to polypharmacy about 4 months after initiating monotherapy, and seniors (65 or older) typically take about 5 months. But curiously, a subgroup of senior patients move from monotherapy, to polypharmacy to no medication within a month of initial claim, Carolyn Martin, associate director of Health Economics and Outcomes Research at Optum, a health technology services company based in Eden Prairie, Minnesota told BreakingMED. Martin reported the findings in a poster here at Psych Congress 2019.

She explained that she and her colleagues identified 1,303 patients prescribed antipsychotics for a number of diagnoses, including anxiety, schizophrenia, depression, etc. All patients were enrolled in health plans for 6 months prior to baseline and claims data were analyzed for 12 months following baseline.

In an interview, Martin explained that the analysis is ongoing. “We have now established what patients are doing. We don’t know why they are adding additional drugs or why they are stopping.” She agreed, for example, that Medicare Part D enrollees may stop medications when their annual medication costs exceed the full-coverage limit, the coverage gap that is known as “the donut hole.” For 2019 this gap occurs when prescription drug costs exceed $3,820.