RT Journal Article
SR Electronic
T1 OpenSAFELY: impact of national guidance on switching anticoagulant therapy during COVID-19 pandemic
JF Open Heart
JO Open Heart
FD British Cardiovascular Society
SP e001784
DO 10.1136/openhrt-2021-001784
VO 8
IS 2
A1 The OpenSAFELY Collaborative
A1 Helen J Curtis
A1 Brian MacKenna
A1 Alex J Walker
A1 Richard Croker
A1 Amir Mehrkar
A1 Caroline Morton
A1 Seb Bacon
A1 George Hickman
A1 Peter Inglesby
A1 Chris Bates
A1 David Evans
A1 Tom Ward
A1 Jonathan Cockburn
A1 Simon Davy
A1 Krishnan Bhaskaran
A1 Anna Schultze
A1 Christopher T Rentsch
A1 Elizabeth Williamson
A1 William Hulme
A1 Laurie Tomlinson
A1 Rohini Mathur
A1 Henry Drysdale
A1 Rosalind M Eggo
A1 Angel Yun Wong
A1 Harriet Forbes
A1 John Parry
A1 Frank Hester
A1 Sam Harper
A1 Ian Douglas
A1 Liam Smeeth
A1 Ben Goldacre
YR 2021
UL http://openheart.bmj.com/content/8/2/e001784.abstract
AB Background Early in the COVID-19 pandemic, the National Health Service (NHS) recommended that appropriate patients anticoagulated with warfarin should be switched to direct-acting oral anticoagulants (DOACs), requiring less frequent blood testing. Subsequently, a national safety alert was issued regarding patients being inappropriately coprescribed two anticoagulants following a medication change and associated monitoring.Objective To describe which people were switched from warfarin to DOACs; identify potentially unsafe coprescribing of anticoagulants; and assess whether abnormal clotting results have become more frequent during the pandemic.Methods With the approval of NHS England, we conducted a cohort study using routine clinical data from 24 million NHS patients in England.Results 20 000 of 164 000 warfarin patients (12.2%) switched to DOACs between March and May 2020, most commonly to edoxaban and apixaban. Factors associated with switching included: older age, recent renal function test, higher number of recent INR tests recorded, atrial fibrillation diagnosis and care home residency. There was a sharp rise in coprescribing of warfarin and DOACs from typically 50–100 per month to 246 in April 2020, 0.06% of all people receiving a DOAC or warfarin. International normalised ratio (INR) testing fell by 14% to 506.8 patients tested per 1000 warfarin patients each month. We observed a very small increase in elevated INRs (n=470) during April compared with January (n=420).Conclusions Increased switching of anticoagulants from warfarin to DOACs was observed at the outset of the COVID-19 pandemic in England following national guidance. There was a small but substantial number of people coprescribed warfarin and DOACs during this period. Despite a national safety alert on the issue, a widespread rise in elevated INR test results was not found. Primary care has responded rapidly to changes in patient care during the COVID-19 pandemic.Data are available in a public, open access repository. Data management was performed using Python 3.8 and SQL, and regression analysis using Stata 16.1. All code for the OpenSAFELY platform, and for data management and analyses for this study, are available for inspection and reuse under open licenses on GitHub (https://github.com/opensafely/anticoagulant-switching-research). All codelists are available for inspection and re-use from https://codelists.opensafely.org/.