Table 1.

Baseline Characteristics of Medicare Beneficiaries Newly Diagnosed with Atrial Fibrillation, by Adherence to Oral Anticoagulation Measured during the First 30 Days after Diagnosis.

Variable-n(%)	Adherent Users (n=12,073)	Non-Adherent Users (n=5,234)	Non-Users (n=21,965)	P- value
Demographics
Age				<0.001
<65	6.6	6.8	6.7
65-74	38.8	37.5	33.5
>=75	54.7	55.6	59.8
Female sex	55.1	57.0	60.6	<0.001
Race				<0.001
White	88.2	88.1	85.9
Black	6.5	7.4	8.3
Hispanic	1.4	1.3	1.7
Other	3.8	3.3	4.2
Social Determinants				<0.001
Eligibility for Medicaid	23.6	23.5	29.9	<0.001
Eligibility for Low-income	32.0	34.6	44.1
Subsidy
Rural Residence	25.0	22.8	21.7	<0.001
Clinical Characteristics
CHA2DS2-VASc score				<0.001
2-3	29.5	27.4	25.0
4-5	42.6	40.8	39.9
≥6	28.0	31.8	35.1	<0.001
HAS-BLED score a
0-1	7.2	6.8	5.9
2-3	68.3	65.7	61.2
≥4	24.5	27.5	32.9
AMI b	7.3	7.5	9.5	<0.001
Alzheimer's Disease or Dementia b	13.3	14.0	23.9	<0.001
Chronic Kidney Disease b	34.6	38.4	42.7	<0.001
Heart Failure b	45.0	48.9	50.1	<0.001
Diabetes b	45.8	47.0	46.5	0.317
Hypertension b	91.2	91.8	92.3	0.002
Stroke or TIA b	20.8	22.7	23.8	<0.001
Recent Bleeding c	16.2	17.9	22.0	<0.001
Recent Antiplatelet use d	12.5	12.5	15.7	<0.001
Recent NSAID use e	13.1	12.4	13.4	0.137
Liver Disease	1.7	1.4	2.7	<0.001
Alcohol Disorder	2.3	2.0	2.7	0.002
Vascular Disease	29.7	31.6	35.2	<0.001

Abbreviations: AMI=Acute Myocardial Infarction; TIA= Transient Ischemic Attack; NSAIDs=Non-Steroidal Anti-inflammatory Drug.

^aThe HAS-BLED score is calculated as the sum of the following factors: age of 65 years or greater, labile INR, renal disease, liver disease, use of antiplatelet agents or NSAIDs, hypertension, a history of stroke, of major bleeding and of alcohol or drug use.²⁵ Because Medicare claims data does not contain information on INR levels, we calculated the HAS-BLED score as the sum of all factors except labile INR.

^bAMI, Alzheimer’s Disease or related dementia, chronic kidney disease, heart failure, diabetes, hypertension, and a history of stroke or TIA were defined using the respective CMS Chronic Condition Warehouse definitions of each of these conditions.

^cRecent bleeding was defined as having a claim with ICD-9 codes for bleeding events in the year before index date.^{10,11,28,30-33}

^dRecent antiplatelet use was defined as filling a prescription for aspirin, clopidogrel, prasugrel, dipyridamol, ticlopidine or ticagrelor in the six months before index date.^{10,11,28,30-33}

^eRecent NSAID use was defined as filling a prescription for diclofenac, ibuprofen, naproxen, ketoprofen, fenoprofen, flurbiprofen, piroxicam, meloxicam, mefenamic acid or indomethacin in the six months before index date.^{10,11,28,30-33}