They are also more convenient to use because of the tight blood-sample monitoring and regular dose adjustment needed for warfarin treatment.
“We were curious if the introduction of DOACs would help to address the known care gap that frail people with atrial fibrillation are less likely to be prescribed anticoagulant drugs like warfarin because they have more trouble going to the lab frequently for blood work and are at higher risk for bleeding complications,” explained lead investigator Finlay A. McAlister, MD MSc, Canadian VIGOUR Centre, and Department of Medicine, University of Alberta, Edmonton, AB, Canada.
The investigators examined prescribing data for 75,796 adults in Alberta, Canada, who had been discharged from an emergency department or hospital with a new diagnosis of nonvalvular atrial fibrillation between April 1, 2009, and March 31, 2019.
The Hospital Frailty Risk Score, which is based on the presence or absence of 109 diagnoses such as ulcers, falls, osteoporosis, and dementia, was used to define frailty.
More than 17,000 patients met the criteria for being frail, including 76% of patients who were elderly and 24% of patients under 65 years old.
Most of the patients met Canadian guideline criteria for anticoagulation treatment (92.1% of frail patients and 74.2% of non-frail patients). Anticoagulant prescribing increased more in non-frail patients (from 42.4% to 68.2%) than in frail patients (from 29.0% to 52.2%) over the period studied.
Frail patients were still less likely to receive any anticoagulant, and even if anticoagulated, frail patients were 34% less likely to receive a DOAC than warfarin. Patients younger than 65 were more likely to receive a DOAC prescription.
DOACs are generally covered by younger patients’ work-related drug benefits, while the government-sponsored drug program in Canada for patients older than 65 requires documentation that the patient was unable to have their blood monitored or had abnormal results while on warfarin.
Researchers hypothesize that clinicians may be more reluctant to anticoagulant elderly frail patients based on the risk of bleeding. But they will also have a higher risk of stroke.
This is a well-designed, clinically important study that is a wake-up call for clinicians on several fronts. It is getting late in the game to consider DOACs as an innovation.