The speed of adoption of new drugs and prescription volume after the amendments in reimbursement coverage: the case of non-vitamin K antagonist oral anticoagulants in South Korea

BACKGROUND: The speed of adoption of new drugs and frequencies of substitutions leads to changes in health care expenditures as well as patient outcomes. In this study, we aim to understand the speed of adoption of new drugs and their prescription volume in health care institutions and evaluate the impact of policy options to manage pharmaceutical expenditure. METHODS: We conducted a retrospective cohort study of health care institutions prescribing NOACs, including Apixaban, Dabigatran, and Rivaroxaban, to address the speed of adoption and their substitution from October 1, 2010, through December 31, 2015, using the National Health Insurance Service-National Sample Cohort. Two threshold time points, including the extension of reimbursement with the need for the letter of opinion and the withdrawal of the letter of opinion, were noted in this study. Then, we applied a survival analysis to elucidate factors that affected the speed of adoption of NOACs, and interrupted time series analysis to estimate the effect of amendments in reimbursement coverage in prescription volume. RESULTS: Among 934 health care institutions in a study population, 334 institutions (36%) had prescribed NOACs at least one time during the study period, indicating that health care institutions were conservative in adopting new drugs. However, the speed of adoption was related to the characteristics of health care institution. We also found that prescriptions of NOACs before the withdrawal of the need for the letter of opinion were marginal, and the prescription volume of NOACs was significantly increased after the withdrawal of a letter of opinion. CONCLUSIONS: Health care institutions were conservative in adopting new drugs, and the speed of adoption is not closely related to an increased prescription volume in the short run. Thus, policies that are centered on managing pharmaceutical expenditure should be devised with considering the impact of introducing new drugs in the long run. A letter of opinion, which was devised to manage prescriptions of NOACs, was effective in managing pharmaceutical expenditures in health care institutions, particularly for tertiary institutions. Conversely, the withdrawal of the need for the letter of opinion should be implemented with caution.