Smith, Laura Barrie

Background: Physicians’ professional networks are an important source of new medical information and have been shown to influence the adoption of new treatments, but it is unknown how physician networks impact the de-adoption of harmful practices. Methods: We analyzed changes in physicians’ use of dronedarone after the PALLAS trial (Palbociclib Collaborative Adjuvant Study; November 2011) showed that dronedarone increased the risk of death from cardiovascular events among patients with permanent atrial fibrillation. Deidentified administrative claims from the OptumLabs Data Warehouse were combined with physicians’ demographic information from the Doximity database and publicly available data on physicians’ patient-sharing relationships compiled by the Centers for Medicare and Medicaid Services. We used a linear probability model with an interrupted linear time trend specification to model the impact of the PALLAS trial on physicians’ dronedarone usage between 2009 and 2014. Results: Before the PALLAS trial, the use of dronedarone was increasing by 0.22 percentage points per quarter (95% CI, 0.19–0.25) in our Medicare Advantage sample (N=343 429 patient-quarter observations) and 0.63 percentage points per quarter (95% CI, 0.52–0.75) in our commercially insured sample (N=44 402 patient-quarter observations). After the PALLAS trial and subsequent United States Food and Drug Administration black box warning, physicians in the Medicare Advantage sample with an above-median number of network connections to other physicians decreased their quarterly usage of dronedarone by 0.12 percentage points more per quarter (95% CI, −0.20 to −0.04; P =0.031) than physicians with equal to or below the median number of network connections. Similar patterns existed in the commercially insured sample ( P =0.0318). Conclusions: After controlling for a wide range of patient, physician, and geographic characteristics, physicians with a greater number of network connections were faster de-adopters of dronedarone for patients with permanent atrial fibrillation after the PALLAS trial and subsequent United States Food and Drug Administration black box warning detailed the harmfulness of dronedarone for these patients. Policies for improving physicians’ responsiveness to new medical information should consider utilizing the influence of these important professional network relationships.

AbstractObjectiveTo describe physicians’ variation in de‐adopting concurrent statin and fibrate therapy for type 2 diabetic patients following a reversal in clinical evidence.Data SourcesWe analyzed 2007‐2015 claims data from OptumLabs® Data Warehouse, a longitudinal, real‐world data asset with de‐identified administrative claims and electronic health record data.Study DesignWe modeled fibrate use among Medicare Advantage and commercially insured type 2 diabetic statin users before and after the publication of the ACCORD lipid trial, which found statins and fibrates were no more effective than statins alone in reducing cardiovascular events among type 2 diabetic patients. We modeled fibrate use trends with physician random effects and physician characteristics such as age and specialty.Data ExtractionWe identified patient‐year‐quarters with one year of continuous insurance enrollment, type 2 diabetes diagnoses, and fibrate use. We designated the physician most responsible for patients’ diabetes care based on evaluation and management visits and prescriptions of glucose‐lowering drugs.Principal FindingsFibrate use increased by 0.12 percentage points per quarter among commercial patients (95% CI, 0.10 to 0.14) and 0.17 percentage points per quarter among Medicare Advantage patients (95% CI, 0.13 to 0.20) before the trial and then decreased by 0.16 percentage points per quarter among commercial patients (95% CI, −0.18 to −0.15) and 0.05 percentage points per quarter among Medicare Advantage patients (95% CI, −0.06 to −0.03) after the trial. However, 45% of physicians treating commercial patients and 48% of physicians treating Medicare Advantage patients had positive trends in prescribing following the trial. Physicians’ characteristics did not explain their variation (pseudo R2 = 0.000).ConclusionOn average, physicians decreased fibrate prescribing following the ACCORD lipid trial. However, many physicians increased prescribing following the trial. Observable physician characteristics did not explain variations in prescribing. Future research should examine whether physicians vary similarly in other de‐adoption settings.