Despite Advances, Room for Improvement in Anticoagulation Exists for Older Adults

An analysis of Medicare beneficiaries is providing clinicians and researchers with an updated overview of anticoagulation among older adults with atrial fibrillation in the US.

Results of the study, which included data from 381,000 Medicare beneficiaries with atrial fibrillation receiving treatment from 2010-2020, demonstrate oral anticoagulation initiation rates as well as patient adherence had improved during the study period, but also indicate multiple notable gaps in care and hurdles to optimal prescription of these agents in eligible older adults.

“Our cohort study demonstrates that since the introduction of DOACs, OAC initiation within 12 months of new AF diagnosis has improved in older adults,” wrote investigators. “Nevertheless, substantial practice gap remains, with 67.1% of patients with incident AF in 2020 not being started on OAC within 12 months of the AF diagnosis. Patients with dementia, frailty, and anemia were persistently undertreated with OAC.”

With the initiation of direct oral anticoagulants, many expected the advent of these newer medications to revolutionize uptake of anticoagulation in patients with atrial fibrillation. Despite this, under-treatment of older adults with an indication for anticoagulation remains a persistent gap to optimal management of atrial fibrillation among the US’s aging population. To better understand contemporary trends in anticoagulation, a team from Boston-based medical institutions sought to explore trends in oral anticoagulation and nonadherence in a retrospective cohort analysis leveraging deidentified data from the Optum’s Clinformatics Data Mart recorded between January 1, 2010, and December 31, 2020.

Limiting their analyses to beneficiaries of Medicare Advantage plans aged 65 years and older with atrial fibrillation and elevated risk of ischemic stroke, investigators identified 381,488 oral anticoagulant eligible adults with incident atrial fibrillation for inclusion in their analyses. Overall, the range of patients per year with incident atrial fibrillation was 12,603-51,236. During the period of interest, the mean age of patients diagnosed ranged from 77.2 (SD, 6.1) years to 77.4 (SD, 6.8) years and the proportion of women ranged from 51.8% to 49.8%.

The primary outcomes of interest for the investigators’ analyses were oral anticoagulation vitiation within 12 months after a first diagnosis of atrial fibrillation and nonadherence with oral anticoagulation, which was defined as less than 80% of days covered among patients newly started on oral anticoagulation in each year. For the purpose of analysis, coexisting dementia, frail, and anemia were used as exposures of interest.

Upon analysis, results indicated rates of oral anticoagulation initiation within 12 months after incident atrial fibrillation diagnosis increased from 20.2% in 2010 to 32.9% in 2020. During the study period, uptake of DOACs increased from 1.1% in 2010 to 30.9% in 2020, while rates of warfarin initiation decreased from 19.1% in 2010 to 2.0% in 2020. When assessing adherence, investigators found the median proportion of days covered increased from 77.6% (IQR, 41.0%-96.4%) in 2010 to 90.2%(57.4%-98.6%) in 2020 and oral ant nonadherence decreased from 52.2% in 2010 to 39.0% in 2020.

Further analysis demonstrated older age (OR, 0.98 [95%CI, 0.98-0.98]), dementia (OR, 0.57 [95%CI, 0.55-0.58]), frailty (OR, 0.74 [95% CI, 0.72-0.76]), and anemia (OR, 0.75 [95%CI, 0.74-0.77]) were associated with lower odds of OAC initiation. Investigators also pointed out female sex (OR, 1.06 [95% CI, 1.02-1.11]) and higher HAS-BLED (OR, 1.12 [95% CI, 1.08-1.17]) score were associated with greater odds of DOAC initiation while prior hip or pelvic fracture (OR, 0.90 [95%CI, 0.85-0.94]) and a diagnosis of chronic kidney disease (OR, 0.83 [95% CI, 0.80-0.87]) were associated with lower odds of DOAC initiation.

“There are 4 main findings of our study,” investigators added. “First, after the introduction of DOACs, the rate of 12-month initiation of OAC among patients with newly diagnosed AF increased by 12.7%from 2010 to 2020. Second, among OAC initiators, apixaban is now the most widely prescribed OAC. Third, initiation of OAC remains suboptimal in older adults with AF, particularly among those with dementia, frailty, and anemia. Fourth, since the introduction of DOACs, adherence with OAC has improved.”

This study, “Trends in Use of Oral Anticoagulants in Older Adults With Newly Diagnosed Atrial Fibrillation, 2010-2020,” was published in JAMA Network Open.