New blood-thinning medications quickly incorporated into GPs' prescribing habits
In The Netherlands the majority of patients diagnosed with atrial fibrillation (AF) by their general practitioner, starts with a prescription for direct oral anticoagulants (DOACs, a relatively new type of blood-thinning medication). Patients who are already using blood thinners for a diagnosis of atrial fibrillation mainly use vitamin K antagonists (VKA). This was established in research conducted by Nivel. The study was recently published in the scientific journal British Journal of General Practice Open (BJGP Open).
When atrial fibrillation is diagnosed, in most cases a blood thinner (oral anticoagulant) will be prescribed to prevent blood clots and stroke. There are two types of oral anticoagulants: Vitamin K antagonists (VKAs) and Direct Oral Anticoagulants (DOACs). When VKAs are used, frequent checkups of blood values are necessary. In The Netherlands this monitoring is done by specialized thrombosis services. DOACs were introduced in the EU in 2008. In The Netherlands first only medical specialists prescribed them, but since 2016 they are also reimbursed when general practitioners prescribe them. DOACs are used in fixed doses and users do not need regular check-ups of their blood. This is an advantage over VKAs. In hospital care, there is a clear preference for DOACs in the guideline for atrial fibrillation, but in the Dutch guidelines for GPs from 2017, VKAs and DOACs are seen as equivalent when starting OACs for atrial fibrillation if there are no contraindications. Our research shows however that GPs do have a preference. Soon after DOACs became available, GPs prescribe them to 88% of patients starting an oral anticoagulant for atrial fibrillation.
Hardly any switching between different types of oral anticoagulants
When patients are using a blood thinner switching to another blood thinner type is uncommon, both for patients who have recently started the blood thinner, and for patients who have been using them for a longer period of time. As the majority of new patients receive DOACs, the number of patients using a VKA will decrease. Therefore, it is important to reflect on how the necessary check-ups for VKA-users , which are now done by the specialized thrombosis services, can also be safely organized in the future. After all, there will always be a minority of patients for whom a DOAC is contraindicated. These patients will continue to rely on a VKA with associated necessary check-ups.
The data for this study came from the Nivel Primary Care Database, using data on the years 2017-2018. We selected 214 GP practices, from whom we had data on medication and diagnoses. Of these, 14,068 patients had atrial fibrillation and were using a blood thinner in 2018.