Changes to anticoagulation during the pandemic

In March 2020, as COVID-19 was declared a pandemic and efforts were made to reduce face-to-face consultations with patients, NHS England (2020) devised a rapid plan to switch patients who had previously had a blood clot and were on warfarin therapy to a direct oral anticoagulant (DOAC).

The goal of warfarin—a vitamin K antagonist and the most widely prescribed anticoagulant therapy—is to prevent blood clotting. It does this by delivering the lowest effective dose of anticoagulant to maintain the target international normalised ratio (INR). This measures how long it takes a person's blood to clot. Warfarin thins the blood to prevent blood clots, but not so much that bleeding risk increases. Trying to get this delicate balance right requires regular INR monitoring—a tall order for overextended healthcare resources during a pandemic.

Like most decisions made during the COVID-19 pandemic, the decision to switch as many patients on warfarin therapy as possible to a DOAC to reduce INR blood testing frequency while still keeping patients safe, was made quickly. It made sense, but without the time to consider all aspects or potential consequences, it was not without its challenges. There were many aspects to be weighed and considered in switching patients' anticoagulant therapy.