Lifeday coverage of oral anticoagulants and one-year relative survival in patients with atrial fibrillation: a population-based study in Estonia

Background: Routine oral anticoagulation (OAC) is recommended for almost all high-risk patients with atrial fibrillation, yet registries show that OACs are still underused. Our aim was to study the lifeday coverage (LDC) of OAC prescriptions and its relationship with one-year mortality rates of AF patients aged ≥ 65 in Estonia for the years 2019 and 2020.

Methods: Medical data for AF patients aged ≥ 65 years from 2018 and alive as of 01.01.2019 (cohort I) and new AF documentation from 2019 and alive as of 01.01.2020 (cohort II) was obtained from the Health Insurance Fund's electronic database. The data was linked to the nationwide Estonian Medical Prescription Centre's database of prescribed OACs. For LDC analysis, daily doses of guideline-recommended OACs were used. The patients were categorized into three LDC groups: 0%, 1-79%, and ≥ 80%. The data was linked to the Estonian Causes of Death Registry to establish the date of death and mortality rate for the whole Estonian population aged ≥ 65.

Results: There were 34,018 patients in cohort I and 9,175 patients with new AF documentation (cohort II), previously not included in cohort I. Of the patients, 77.7% and 68.6% had at least one prescription of OAC in cohorts I and II respectively. 57.4% in cohort I and 44.5% in cohort II had an LDC of ≥ 80%. The relative survival estimates at 1 year for LDC lifeday coverage groups 0%, 1-79%, and ≥ 80% were 91.2%, 98.2%, and 98.5% (cohort I), and 91.9%, 95.2%, and 97.6% (cohort II), respectively.

Conclusions: Despite clear indications for OAC use, LDC is still insufficient and anticoagulation is underused for stroke prevention in Estonia. Further education of the medical community and patients is needed to achieve higher lifeday coverage of prescribed OACs.