P-509: Oral anticoagulant prescribing in people aged ≥ 75 years with atrial fibrillation in the UK pre- and post-introduction of direct oral anticoagulants: a study protocol

摘要

Introduction: Direct oral anticoagulants (DOACs) entered the UK market from 2008 providing an alternative to warfarin and have subsequently been recommended in guidelines for stroke prevention in AF. We present a study protocol to describe changes in the prescribing of oral anticoagulants (OACs) to people aged ≥ 75 years in UK general practice before and after the introduction of DOACs. Methods and analysis: A cohort of patients with a diagnosis of AF will be identified from general practice data in the Clinical Practice Research Datalink (CPRD) from 1/1/03 to 27/12/17. Patients enter the cohort at either: start of study period, first AF diagnosis, or 75th birthday, and leave if they leave the practice, die or the practice stops contributing data. Exposure will be defined as ≥ 1 prescription issued for an OAC during the study period. Prevalent users will be defined as those entering on or issued an OAC in the year preceding entry. Patients started on an OAC during the study with no prescriptions in the preceding year will be defined as incident users. Incidence and prevalence of OAC prescribing, demographics and patient characteristics will be described during three time periods: 2003-2007 (pre-DOAC), 2008-2012 (post DOAC introduction pre-licence) and 2013-2017 (post DOAC licensing). Differences in persistence with the different OACs and switching between OACs will be investigated. Key conclusions: The results will indicate whether DOACs have changed the rate of OAC prescribing for older people and whether they have affected the types of patients for whom OACs are prescribed.