DOAC Prescriptions Gradually Displaced Warfarin in AF, CKD Treatment

A new study published in the Journal of Cardiovascular Pharmacology and Therapeutics found that direct oral anticoagulants (DOACs) have gradually replaced warfarin in treating patients with atrial fibrillation (AF) and chronic kidney disease (CKD), with patients receiving anticoagulation increasing over time.

Patients with CKD, more than 45 million of whom are in the United States, have a higher burden of cardiovascular disease, including AF. DOACs have become an alternative treatment option to warfarin and has similar safety and efficacy outcomes in patients with CKD. This study aimed to find “how oral anticoagulant prescribing for Medicare beneficiaries with AF and CKD has evolved over time.”

CMS Parts A, B, and D billing files were used to identify patients with diagnoses of AF and their stage of CKD. These files were also used to identify anticoagulant prescriptions, prescriber specialty, and patient characteristics. Patients continuously enrolled in Medicare were the only participants studied.

Patients who were prescribed and used apixaban, warfarin, dabigatran, rivaroxaban, or edoxaban from January 1, 2011, to December 31, 2017, were identified for this study. Patients were excluded if they had used any oral anticoagulant in the previous year. Patients with other indications of anticoagulation, with a history of specific valvular heart diseases or end-stage renal disease (ESRD), and those without CKD stage 3, 4, or 5 in the previous year were also excluded.

There were 22,739 participants included in this study who had AF and CKD stages 3, 4, or 5 and received a prescription for an anticoagulant:

• 6738 (29.6%) received apixaban
• 904 (17.2%) received rivaroxaban
• 1568 (6.9%%) received dabigatran
• 10,529 (46.3%) received warfarin

The mean (SD) age of the group was 78.8 (8.6) years and 51.0% were women. The majority of the group (86.7%) were White and CKD stage 3 was the most common (84.3%).

Looking at trends over time, the researchers found that cardiologists represented the largest prescriber specialty, but that primary care providers issued the most prescriptions (45.9%). Cardiologists were the first group to prescribe DOACs more often than warfarin, in 2014. Primary care providers and other prescribers began preferring DOACs over warfarin in 2015.

A total of 4222 (66.5%) of patients with CKD stage 3 and 510 (50.8%) of patients with CKD stage 4 to 5 were prescribed a DOAC by a cardiologist.

Primary care providers prescribed a total of 4409 (50.8%) DOACs to patients with CKD stage 3; other care providers prescribed 2038 (50.8%) DOACs to patients with CKD stage 3.

In CKD stages 4 to 5, 659 (37.5%) and 306 (37.7%) patients were prescribed a DOAC by their primary care provider, or another provider, respectively.

A higher likelihood of being prescribed a DOAC was found in patients of older age (OR, 1.16; 95% CI, 1.10-1.33 in patients 76-80 years and OR, 1.15; 95% CI, 1.01-1.32 in patients aged 81-85 years) and living in urban areas. Less DOAC was found in patients with worsening CKD (OR, 0.59; 95% CI, 0.55-0.64 in CKD stage 4 and OR, 0.44; 95% CI, 0.33-0.59 in CKD stage 5).

History of cancer, alcohol abuse, use of nonsteroidal anti-inflammatory drugs, antidiabetics, falls, and antiarrhythmics were associated with a patient more likely to receive DOACs. An increasing disability proxy score was associated with a greater likelihood of use of a DOAC compared with warfarin (OR, 1.27; 95% CI, 1.15-1.41 for score 5-6 and OR, 1.30; 95% CI, 1.16-1.45). DOACs were more likely in patients who received an initial prescription from cardiologists.

About 29.3% of patients prescribed warfarin at baseline continued to use it until the end of follow up whereas 63.4% stopped using anticoagulants and only 7.3% switched from warfarin to a DOAC.

There are some limitations to this study. Measured creatinine and estimated glomerular filtration rates were not used to define CKD. This study took place in the United States and may not be generalizable to other countries. The disability proxy score has not been validated. Long-term use of these drugs cannot be assessed as this study focused on “intention-to-treat.”

The researchers concluded that patients using Medicare who have been diagnosed with AF and CKD stages 3, 4, or 5 and aren’t receiving dialysis have had increasing usage of DOACs, displacing warfarin.

Reference

Reyes JL, Herzog CA, Yan H, Roetker NS, Wetmore JB. Prescribing patterns of direct-acting oral anticoagulants in patients with atrial fibrillation and chronic kidney disease: a retrospective cohort analysis. J Cardiovasc Pharmacol Ther. 2022;27:1-10. doi:10.1177/10742484221142220