Table 1.
Characteristics of the derivation and validation cohorts
| Variable | Derivation* (N = 390) |
Validation* (N = 663) |
P value† |
|---|---|---|---|
| Age | |||
| < 45 | 65 (17) | 135 (20) | < 0.001 |
| 45 – 55 | 74 (19) | 131 (20) | |
| 55 – 65 | 103 (26) | 219 (33) | |
| 65 – 75 | 83 (21) | 116 (18) | |
| 75+ | 65 (17) | 60 (9) | |
| Female gender | 119 (31) | 250 (38) | 0.02 |
| African American race | 174 (45) | 466 (71) | < 0.001 |
| Employment status | |||
| Working | 128 (33) | 167 (25) | < 0.001 |
| Unemployed | 34 (9) | 49 (7) | |
| Retired | 143 (37) | 192 (29) | |
| Disabled | 81 (21) | 251 (38) | |
| Annual income | |||
| < $15,000 | 109 (33) | 228 (41) | < 0.001 |
| $15,000 – $20,000 | 99 (30) | 45 (8) | |
| > $20,000 | 122 (37) | 282 (51) | |
| Insurance status | |||
| Private | 215 (56) | 276 (42) | < 0.001 |
| VA/Medicare/Other | 124 (32) | 272 (41) | |
| Medicaid/None | 45 (12) | 110 (17) | |
| Number MD visits in previous year | |||
| < 4 | 101 (26) | 122 (19) | < 0.001 |
| 4 – 12 | 187 (48) | 295 (45) | |
| > 12 | 98 (25) | 242 (37) | |
| Smoking status | |||
| Never | 141 (36) | 275 (42) | < 0.001 |
| Past | 185 (47) | 235 (36) | |
| Current | 64 (16) | 148 (22) | |
| Body Mass Index | |||
| < 25 | 122 (32) | 185 (28) | 0.11 |
| 25 – 30 | 125 (32) | 189 (29) | |
| > 30 | 140 (36) | 280 (43) | |
| Warfarin indication | |||
| AFib/AFlutter | 188 (48) | 214 (32) | < 0.001 |
| DVT/PE | 116 (30) | 343 (52) | |
| Other | 86 (22) | 105 (16) | |
| Previously used warfarin | 96 (25) | 209 (32) | 0.02 |
| History of hypertension | 192 (49) | 461 (70) | < 0.001 |
| History of diabetes | 107 (27) | 190 (29) | 0.71 |
| History of peptic ulcer disease | 36 (9) | 98 (15) | 0.01 |
| History of congestive heart failure | 78 (20) | 141 (21) | 0.65 |
AFib indicates atrial fibrillation; AFlutter, atrial flutter; DVT, deep vein thrombosis; VA, Veterans Affairs.
*
All values are reported as N (%)
†
P values are based on the chi-square test.