OBJECTIVES: To compare prescription trends, costs, switch patterns, and mean adherence among oral anticoagulants (OACs) in the Texas Medicaid population.

METHODS: Texas Medicaid prescription claims data from July 1, 2010 to December 31, 2015 were analyzed. All OAC prescriptions for patients aged 18-63 with ≥1 prescription claim for an OAC were included in utilization and expenditure trend analyses. Switch patterns and adherence, measured by the proportion of days covered (PDC), over 1 year were analyzed for patients newly initiated on OAC therapy between January 1, 2011 and December 31, 2014 and having ≥2 prescription claims. Adherence was measured only for direct oral anticoagulants (DOACs) as frequent dosage adjustments for warfarin limit PDC estimation accuracy.

RESULTS: Over the 5.5-year study period, DOAC use increased steadily and the proportion of OAC prescription expenditures accounted for DOACs increased substantially. By December 2015, DOACs accounted for a third of anticoagulant prescription claims and >90% of total oral anticoagulant prescription expenditures. 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 (dabigatran = 17.9%, rivaroxaban = 24.5% and apixaban = 15.6%), compared to warfarin (9.2%) [X(3, N = 7,397) = 190.9, p < 0.001]. The overall mean PDC was 0.71±0.21, with no significant difference between patients on dabigatran, rivaroxaban and apixaban. Using an PDC cutoff point of 0.80 to indicate adherence/non-adherence, 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 as compared to warfarin initiators and non-adherence to DOACs is needed to understand the challenges related to DOAC adoption in practice and to improve patient outcomes.