Direct Oral Anticoagulant Prescription Trends, Switching Patterns, and Adherence in Texas Medicaid

OBJECTIVES: To compare prescription trends, costs, switch patterns, and mean adherence among oral anticoagulants in the Texas Medicaid population. STUDY DESIGN: Secondary analysis of Medicaid prescription claims data. METHODS: All oral anticoagulant prescriptions for patients aged 18 to 63 years with 1 or more prescription claims for an oral anticoagulant from July 1, 2010, to December 31, 2015, were included in utilization and expenditure trend analyses. Switch patterns and adherence, measured by the proportion of days covered (PDC), were analyzed over 1 year for patients newly initiated on oral anticoagulant therapy. RESULTS: Over the 5.5-year study period, direct oral anticoagulant (DOAC) use increased steadily and the proportion of oral anticoagulant prescription expenditures accounted for by DOACs increased substantially. By December 2015, DOACs accounted for one-third of anticoagulant prescription claims and more than 90% of total oral anticoagulant prescription expenditures. The mean cost per prescription was 30 times higher for DOACs than warfarin. A higher proportion of patients with a DOAC as an index drug switched drugs. The overall mean +/- SD PDC was 0.71 +/- 0.21, with no significant differences among patients on dabigatran, rivaroxaban, and apixaban. Using a PDC cutoff point of 0.80 to indicate adherence (vs nonadherence), 42% of patients were categorized as adherent. CONCLUSIONS: Texas Medicaid prescription data show a gradual increase in DOAC use with a rapid increase in prescription expenditures. Further exploration of the causes of higher switch rates among DOAC initiators compared with warfarin initiators and nonadherence to DOACs is needed to understand the challenges related to DOAC adoption in practice and to improve patient outcomes.