The introduction of DOACs has increased the use of anticoagulants to prevent stroke in patients with non-valvular AF.

The study comprised almost 2,000 patients from more than 3,000 admissions at a tertiary hospital in south-east Queensland between 2012 and 2015. The patients had a mean age of 75.5 years and most (79.7%) had a CHA₂DS₂VA score of ≥2.

The study, published in Heart, Lung and Circulation, found the number of patients on no anticoagulant therapy from admission to discharge significantly decreased across all CHA₂DS₂VA categories during the first two admissions.

In return there was a significant increase in the number of patients initiated on either warfarin or a DOAC.

For example, in patients with a CHA₂DS₂VA score of ≥2 and eligible for anticoagulation, the numbers on anticoagulants increased from 45.5% on first admission to 81.4% on discharge (p<0.001).

There was a similar pattern at second admission with the number of patients not on anticoagulants decreasing across all CHA₂DS₂VA scores.

However during this second admission there was a significant increase in patients initiated on DOACs but not on warfarin.

This included a significant increase in the number of patients initiated on DOACs for CHA₂DS₂VA scores of 1 (24.0% to 45.3%; p<0.01) and CHA₂DS₂VA scores of 2 (31.1% to 41.3%; p<0.01).

And the number of patients on anticoagulants with a CHA₂DS₂VA score of 0 suggested there was also some overuse.

“This study found a decline in warfarin usage during the study period and increased usage of the DOACs, particularly rivaroxaban,” it said.

“High rivaroxaban prescribing in Queensland was also reported in the Drug Utilisation Sub-Committee review and, in agreement with their observation, the listing of this anticoagulant on the hospital formulary would be the predominant influencing factor.”

Use of dabigatran and apixaban remained low and below that of warfarin at all times during the study period.

The study also noted similar rates of discontinuation from warfarin or DOACs during the first two admissions, but more patients discontinuing from warfarin on subsequent admissions.

Documented reasons for changing from warfarin to DOAC included erratic INRs, and non-compliance either with dosing or blood tests.

“There remains potential to improve prescribing in accordance with current guidelines to ensure individuals are
receiving appropriate anticoagulation,” the study concluded.