Patient and provider-level factors associated with changes in utilization of treatments in response to evidence on ineffectiveness or harm.

High-quality health care not only includes timely access to effective new therapies but timely abandonment of therapies when they are found to be ineffective or unsafe. Little is known about changes in use of medications after they are shown to be ineffective or unsafe. In this study, we examine changes in use of two medications: fenofibrate, which was found to be ineffective when used with statins among patients with Type 2 diabetes (ACCORD lipid trial); and dronedarone, which was found to be unsafe in patients with permanent atrial fibrillation (PALLAS trial). We examine the patient and provider characteristics associated with a decline in use of these medications. Using Medicare fee-for-service claims from 2008 to 2013, we identified two cohorts: patients with Type 2 diabetes using statins (7 million patient-quarters), and patients with permanent atrial fibrillation (83 thousand patient-quarters). We used interrupted time-series regression models to identify the patient- and provider-level characteristics associated with changes in medication use after new evidence emerged for each case. After new evidence of ineffectiveness emerged, fenofibrate use declined by 0.01 percentage points per quarter (95% CI - 0.02 to - 0.01) from a baseline of 6.9 percent of all diabetes patients receiving fenofibrate; dronedarone use declined by 0.13 percentage points per quarter (95% CI - 0.15 to - 0.10) from a baseline of 3.8 percent of permanent atrial fibrillation patients receiving dronedarone. For dronedarone, use declined more quickly among patients dually-enrolled in Medicare and Medicaid compared to Medicare-only patients (P < 0.001), among patients seen by male providers compared to female providers (P = 0.01), and among patients seen by cardiologists compared to primary care providers (P < 0.001).