The impact of switching patients with non-valvular Afib from warfarin to DOACs in terms of the burden caused by the complications of the disease

Context With the simultaneous presence of Vitamin K Antagonists (VKAs) and Direct Oral Anticoagulants (DOACs) as anticoagulants in the Belgian market for the treatment of Atrial Fibrillation (Afib), there has been an evolution in the prescription behavior since the introduction of the newer agents, as well as an impact on stroke prevention. Aim The aim is to explore the prescription behavior of oral anticoagulants (OACs) as well as the prevalence and incidence of Afib in the Belgian setting from 2002 to 2019 based on the integrated computerized network (INTEGO) database, while also exploring the impact of switching patients with non-valvular Afib from VKAs to DOACs in terms of the burden caused by stroke as a complication of the disease. Methods Data were obtained from INTEGO, a Flemish general practice-based morbidity registration network. Inclusion criteria were at least one GP contact between 2002 and 2019, including yearly prevalent and incident chronic Afib cases, with at least 1 year follow-up. Both OAC classes were included, and drugs and laboratory tests costs were retrieved respectively from the Belgian Centre for Pharmacotherapeutic Information (BCFI) and INAMI sites, based on the 2019 public prices. The number of DALYs was based on the Global Burden of Disease (GBD) literature. The CHA2DS2-VASc score was used as stroke risk stratification tool at time of diagnosis. We conducted cost-utility analyses for 2012-2019 accounting for the global benefit, in terms of (cost of prevented stroke / DALY), of switching above 65-year-old patients in Flanders under VKAs to DOACs, based on the real 2019 numbers in a first scenario, and the results if all anticoagulation eligible Afib patients in Flanders were switched to DOACs in scenario 2. We calculated a Number Needed to Switch (NNSw) to estimate the number of prevented strokes per year. Results Total population with Afib consisted of 8508 patients. An important increase is perceptible in both prevalence and incidence among the above 75 years old. A striking increase of OACS use is observed in CHA2DS2- VASc scores of 1 and at least 2, simultaneously with an overtaking in the use of DOACs starting the second semester of the year 2012 compared to VKAs. The incremental cost effectiveness ratio (ICER) of scenario 1 was 647 €/DALY of prevented stroke and 1,167 €/DALY of prevented stroke for scenario 2. Conclusion In this registry-based study, we found a significant positive trend in OAC and DOACs use in Flanders between 2002 and 2019, as well as an increasing prevalence and incidence in above 75 years-old specifically. Scenarios 1 and 2 are cost-effective when compared to a threshold of 20 000 €/DALY.