Temporal and spatial variation in the prescribing of oral anticoagulants in Scotland - a nationwide record linkage study

Background: Oral anticoagulants (OACs) are widely used in clinical practice to prevent thromboembolic events such as strokes. Following the introduction of direct oral anticoagulants (DOACs) since 2009, major changes in treatment guidelines and prescribing practices have been observed in several countries. The aims of this study are to describe changes in prescribing patterns of oral anticoagulants over time in Scotland; and to evaluate regional variation of their use.

Methods: Retrospective cohort study using linked routinely collected administrative data, comprising patients who received at least one prescription for any oral anticoagulant between January 2009 and December 2017. Analyses include: medicine update and geographical distribution; incidence/prevalence rates; and patient characteristics at time of first OAC prescription.

Results: A total of 7,900,564 prescriptions for OACs were issued between 2009 and 2017: 955,420 for DOACs, and 6,945,144 for vitamin-K antagonists (VKAs). During the study period, the overall number of OAC prescriptions steadily increased year on year; the use of DOACs increased considerably over time, with the share of VKAs among all prescriptions dropping to 64.7% by 2017. There were, however, wide geographical variations in the use of DOACs vs VKAs (ranging from 51.0% to 83.2%), and variations in the specific DOACs most commonly prescribed. Patient characteristics to be presented.

Conclusion: This study provides an in-depth overview of how prescribing of OACs has evolved in Scotland since the introduction of DOACs in 2009. This information will be useful for both clinical practice and further research.