Table 1. Participant Demographics, Medical History, and Medications at Baseline in a Study of the Association of Rivaroxaban vs Apixaban With Major Ischemic or Hemorrhagic Events in Atrial Fibrillationa,b.
| Characteristic | Unweighted | Weighted | ||||
|---|---|---|---|---|---|---|
| Rivaroxaban, % | Apixaban, % | Standardized difference | Rivaroxaban, % | Apixaban, % | Standardized difference | |
| No. of participants | 227 572 | 353 879 | 227 572 | 353 879 | ||
| Anticoagulant dose reduced | 23.0 | 23.2 | 0.0039 | 23.2 | 23.1 | 0.0012 |
| Demographics | ||||||
| Age, mean (SD), y | 76.3 (6.8) | 77.4 (7.2) | 0.1586 | 77.0 (7.1) | 77.0 (7.0) | 0.0023 |
| Year anticoagulant started, mean | 2015.5 | 2016.3 | 0.5409 | 2016.0 | 2016.0 | 0.0018 |
| Women | 48.3 | 51.4 | 0.0627 | 50.0 | 50.0 | 0.0007 |
| Men | 51.7 | 48.6 | 0.0627 | 50.0 | 50.0 | 0.0007 |
| Race and ethnicityc | ||||||
| Asian | 1.6 | 1.3 | 0.0205 | 1.5 | 1.4 | 0.0014 |
| Black | 3.6 | 3.7 | 0.0017 | 3.6 | 3.7 | 0.0008 |
| Hispanic | 1.2 | 1.0 | 0.0182 | 1.1 | 1.0 | 0.0087 |
| North American Native | 0.3 | 0.2 | 0.0162 | 0.3 | 0.2 | 0.0092 |
| White | 92.0 | 92.6 | 0.0224 | 92.4 | 92.4 | 0.0020 |
| Other | 1.2 | 1.1 | 0.0100 | 1.1 | 1.2 | 0.0081 |
| Region of residence | ||||||
| West | 16.1 | 14.1 | 0.0567 | 15.0 | 15.0 | 0.0002 |
| Southwest | 10.6 | 10.6 | 0.0007 | 10.6 | 10.6 | 0.0006 |
| Midwest | 22.2 | 21.3 | 0.0226 | 21.5 | 21.5 | 0.0010 |
| Southeast | 33.1 | 36.7 | 0.0747 | 35.4 | 35.3 | 0.0020 |
| Northeast | 17.9 | 17.3 | 0.0153 | 17.5 | 17.6 | 0.0018 |
| Dual Medicare-Medicaid enrollment | 13.9 | 12.8 | 0.0332 | 13.1 | 13.2 | 0.0032 |
| Cardiologist-prescribed anticoagulant | 49.1 | 49.0 | 0.0030 | 49.8 | 49.6 | 0.0037 |
| Medical history (past year unless otherwise noted) | ||||||
| CHA2DS2-VASc score, meand | 4.2 | 4.4 | 0.1276 | 4.3 | 4.3 | 0.0038 |
| Hypertension | 89.7 | 90.7 | 0.0309 | 90.3 | 90.3 | 0.0008 |
| Diabetes | 35.0 | 34.8 | 0.0031 | 34.8 | 34.9 | 0.0009 |
| Heart failure | 27.9 | 31.2 | 0.0723 | 29.8 | 29.8 | 0.0005 |
| Anemia | 24.6 | 27.1 | 0.0572 | 26.1 | 26.1 | 0.0018 |
| Chronic obstructive pulmonary disease | 21.9 | 22.9 | 0.0249 | 22.3 | 22.3 | 0.0003 |
| Cancer other than nonmelanoma skin cancer | 17.8 | 18.4 | 0.0174 | 18.1 | 18.2 | 0.0008 |
| Bleeding at gastrointestinal or other sites | 14.4 | 15.6 | 0.0314 | 15.1 | 15.1 | 0.0006 |
| Kidney disease, stage 3 or unspecified chronic | 13.8 | 17.9 | 0.1113 | 16.3 | 16.3 | 0.0002 |
| Percutaneous coronary intervention | 11.4 | 12.9 | 0.0447 | 12.3 | 12.3 | 0.0004 |
| Dysphagia/malnutrition | 11.1 | 12.9 | 0.0559 | 12.2 | 12.2 | 0.0004 |
| Coronary artery bypass graft | 9.8 | 10.9 | 0.0339 | 10.4 | 10.4 | 0.0001 |
| Fall | 9.5 | 11.5 | 0.0637 | 10.7 | 10.7 | 0.0003 |
| Cardioversion | 8.9 | 9.4 | 0.0147 | 9.2 | 9.2 | 0.0012 |
| Ischemic stroke, systemic embolism, intracranial bleeding | 8.5 | 9.8 | 0.0466 | 9.3 | 9.2 | 0.0019 |
| Acute kidney failure | 7.6 | 10.5 | 0.0999 | 9.3 | 9.3 | 0.0006 |
| Alzheimer disease and other dementia | 6.9 | 8.2 | 0.0496 | 7.7 | 7.7 | 0.0005 |
| Transient ischemic attack | 6.2 | 6.8 | 0.0263 | 6.6 | 6.5 | 0.0009 |
| Myocardial infarction | 5.6 | 6.8 | 0.0498 | 6.3 | 6.3 | 0.0005 |
| Inpatient discharge past 30 d | 26.7 | 29.0 | 0.0512 | 27.2 | 27.3 | 0.0032 |
| Medication history (past year) | ||||||
| Angiotensin-converting enzyme inhibitor/receptor blocker | 61.5 | 61.7 | 0.0053 | 61.6 | 61.7 | 0.0018 |
| Proton pump inhibitors | 30.2 | 31.5 | 0.0281 | 31.0 | 31.0 | 0.0003 |
| Loop diuretics | 26.1 | 28.9 | 0.0634 | 27.7 | 27.8 | 0.0005 |
| Oral corticosteroids | 24.2 | 25.7 | 0.0334 | 25.0 | 25.0 | 0.0006 |
| Diltiazem or verapamil | 21.5 | 21.1 | 0.0091 | 21.2 | 21.2 | 0.0003 |
| Nonselective nonsteroidal anti-inflammatory drugs | 17.3 | 16.3 | 0.0261 | 16.7 | 16.7 | 0.0002 |
| Platelet ADP P2Y12 receptor inhibitors and other antiplatelet drugs | 15.1 | 16.6 | 0.0404 | 16.0 | 16.0 | 0.0004 |
| Amiodarone | 10.9 | 11.8 | 0.0275 | 11.4 | 11.4 | 0.0005 |
| Home oxygen | 9.8 | 10.6 | 0.0266 | 10.2 | 10.2 | 0.0000 |
| Insulin | 6.1 | 6.6 | 0.0188 | 6.4 | 6.4 | 0.0015 |
| Dronedarone | 2.7 | 2.6 | 0.0099 | 2.7 | 2.6 | 0.0006 |
| No. of medications, mean | 11.8 | 12.1 | 0.0577 | 12.0 | 12.0 | 0.0043 |
Some important covariates selected by the authors as examples of the study covariates; see eTable 5 in the Supplement for the complete set of covariates.
The standardized difference (absolute value of the difference between variable means divided by the SD of the difference) is a measure of balance of covariates between treatment groups, with values <0.1 considered to indicate good balance.
Self-reported race and ethnicity excludes 2369 patients in the rivaroxaban group and 3703 in the apixaban group for whom information was unknown. The categories are as defined in the Medicare data, including the "other" category. The low proportion of Black participants may be related to the substantially lower incidence of atrial fibrillation in this population.29
The CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years [doubled], diabetes, stroke/transient ischemic attack/thromboembolism [doubled], vascular disease [prior myocardial infarction, peripheral artery disease, or aortic plaque]) score for stroke risk stratification25 gives 1 point for age 65-74 y, female sex, heart failure, hypertension, diabetes, vascular disease (myocardial infarction, peripheral artery disease, aortic plaque) and 2 points for age ≥75 y, stroke/transient ischemic attack/thromboembolism. The claims-based version of the score26,27,28 in the table was calculated from Medicare encounters.