Temporal trends in initiation of oral anticoagulants and stroke-free survival among elderly and very elderly patients with new onset atrial fibrillation - a 20-year perspective.

Abstract Background Oral anticoagulants (OACs) significantly reduce the risk of ischemic stroke in patients with atrial fibrillation (AF). However, evidence regarding efficacy of OACs are lacking in the very elderly patients. Aim To examine temporal trends in initiation of OACs and five-year stroke-free survival in the very elderly patients with new onset AF over a time span of 20 years. Methods From the Danish nationwide registries, we identified patients ≥ 65 years of age with new onset AF from 1999 to 2018. The index date was defined as the day of AF diagnosis for outpatients and as the day of discharge for inpatients. Patients with a prescription of OAC, history of bleeding events, or history of stroke/transient ischemic attack prior to index were excluded. Patients were divided into two age groups based on their age at index: 1) 65-84 years (elderly); and 2) ≥ 85 years (very elderly). Patients were further divided into four calendar year groups from 1999-2018, based on the year of inclusion. We investigated the initiation of OACs and calculated the absolute five-year probability of stroke-free survival in both age groups. Results We included 167,122 patients with new-onset AF between January 1st, 1999, and December 31st, 2018. Among the patients, 23.1 % were aged 85 years or older, 48 % were male and 80.5 % had a CHA2DS2-VASc score equivalent to 2 or higher for men and 3 or higher for women. Initiation of OACs increased in both age groups after the guideline implementation of DOACs in 2010 (Figure 1). In the elderly age group, the proportion of patients receiving OACs increased from 50% in 2010 to almost 90% in 2018. In the very elderly age group, the proportion increased from 25% in 2010 to almost 90% in 2018. The probability of the five-year stroke-free survival improved by approximately 15% from 1999 to 2018 in the elderly age group, with no significant changes in the very elderly age group. Conclusion The proportion of elderly AF patients receiving OAC has increased markedly in the last 20 years. Even so, stroke-free survival remains the same among the very elderly patients.Five-year stroke-free survival