DOACs improve appropriate use of anticoagulants in AF


By Mardi Chapman

29 Oct 2020

Under-prescribing and under-anticoagulation to prevent stroke in patients with AF has improved since the introduction of DOACs but still remains a challenge.

An analysis of all stroke admissions at the Canberra Hospital between 2016 and 2018 has found 63% of patients with known AF were appropriately anticoagulated – an INR of ≥2.0 for patients on warfarin and dosing as per Australian guidelines for patients on a DOAC.

This compares favourably to a dismal 9% of patients appropriately anticoagulated in a similar study at the hospital 10 years earlier.

Correspondingly, the incidence of under-anticoagulation reduced from 91% in the 2009 study to 37% in the recent study.

“This is gratifying but the results imply that there are still large numbers of patients who were either not anticoagulated or under-anticoagulated on admission, suggesting that under-prescribing and/or non-compliance remain ongoing issues,” the study said.

“There was an 11% increase [since 2009] in patients with known AF who were not anticoagulated but this difference did not reach significance.”

Warfarin was the only anticoagulant used in the patients ten years ago but the split is now 66% DOAC and 34% warfarin use.

The study, published in the Internal Medicine Journal, found more patients on DOAC were appropriaely anticoagulated (74%) than those on warfarin (41%).

Most patients were subsequently discharged with appropriate anticoagulation with almost three quarters (72%) on a DOAC and 28% on warfarin.

“There was a reduction in the number of patients without contraindication to anticoagulation on discharge (7% vs 28%). This may have been due to change in clinical practice, with perceived contraindications to anticoagulation becoming less stringent since the introduction of DOAC therapy.”

The study said there was no change in the prevalence of AF over the 10 years between the two studies, but a significantly higher proportion of patients were appropriately anticoagulated on recent admissions.

“Possible reasons for this include: (i) overall increase in DOAC use; (ii) improved maintenance of therapeutic INR on warfarin; and (iii) improved compliance with DOAC therapy.”

“Overall, DOAC were more consistently correctly prescribed than a correct INR was achieved on warfarin. This almost certainly reflects relative ease of prescribing and monitoring,” the study said.

The research team, anchored by senior investigator Professor Christian Lueck, concluded that future studies were needed to determine what contributes to under-prescribing/under-anticoagulation and to explore interventions which might improve matters.

“Systems to help primary care providers monitor anticoagulation in the community may assist, as might further education of health practitioners regarding anticoagulant prescribing in AF.”

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