Who Were the Early Adopters of Dabigatran? An Application of Group-based Trajectory Models

Abstract

Background: Variation in physician adoption of new medications is poorly understood. Traditional approaches (eg, measuring time to first prescription) may mask substantial heterogeneity in technology adoption. Objective: Apply group-based trajectory models to examine the physician adoption of dabigratran, a novel anticoagulant. Methods: A retrospective cohort study using prescribing data from IMS Xponenem on all Pennsylvania physicians regularly prescribing anticoagulants (n=3911) and data on their characteristics from the American Medical Association Masterfile. We examined time to first dabigatran prescription and group-based trajectory models to identify adoption trajectories in the first 15 months. Factors associated with rapid adoption were examined using multivariate logistic regressions. Outcomes: Trajectories of monthly share of oral anticoagulant prescriptions for dabigatran. Results: We identified 5 distinct adoption trajectories: 3.7% rapidly and extensively adopted dabigatran (adopting in <3 mo with 45% of prescriptions) and 13.4% were rapid and moderate adopters (< 3 mo with 20% share). Two groups accounting for 21.6% and 16.1% of physicians, respectively, were slower to adopt (6-10 mo post-introduction) and dabigatran accounted for <10% share. Nearly half (45.2%) of anticoagulant prescribers did not adopt dabigatran. Cardiologists were much more likely than primary care physicians to rapidly adopt [odds ratio (OR) = 12.2; 95% confidence interval (CI), 9.27-16.1] as were younger prescribers (age 36-45 y: OR= 1.49, 95% CI, 1.13-1.95; age 46-55: OR = 1.34, 95% CI, 1.07-1.69 vs. >55 y). Conclusions: Trajectories of physician adoption of dabigatran were highly variable with significant differences across specialties. Heterogeneity in physician adoption has potential implications for the cost and effectiveness of treatment.