Table 1.
Baseline Characteristics Before and After PS Matchinga
| Characteristics | Before PS Matching | After PS Matchinga | ||||
|---|---|---|---|---|---|---|
| Aspirin (N=34 679) | Clopidogrel (N=7611) | P Value | Aspirin (N=6443) | Clopidogrel (N=6443) | P Value | |
| Age (y), mean±SD | 67.4±13.7 | 71.8±12.9 | <0.001 | 71.8±16.3 | 71.4±13.2 | 0.140 |
| BMI, mean±SDb | 24.8±3.89 | 24.2±3.91 | <0.001 | 24.1±3.73 | 24.2±3.92 | 0.210 |
| Hospitalization length (d), median (interquartile range) | 7 (7) | 11 (16) | <0.001 | 9 (14) | 10 (15) | 0.340 |
| Male, n (%) | 21 159 (61.0) | 4539 (59.6) | 0.026 | 3878 (60.2) | 3898 (60.5) | 0.719 |
| Obesity, n (%)c | 7974 (23.0) | 1492 (19.6) | <0.001 | 1328 (20.6) | 1448 (22.5) | 0.010 |
| TOAST subtype, n (%) | ||||||
| LAA | 9921 (28.6) | 2580 (33.9) | <0.001 | 2204 (34.2) | 2147 (33.3) | 0.514 |
| SVD | 17 113 (49.4) | 2960 (38.9) | 2510 (39.0) | 2593 (40.3) | ||
| Cardioembolism | 1816 (5.24) | 731 (9.60) | 635 (9.86) | 598 (9.28) | ||
| Specific cause | 375 (1.08) | 85 (1.12) | 68 (1.06) | 68 (1.06) | ||
| Undetermined cause | 5454 (15.7) | 1255 (16.5) | 1026 (15.9) | 1037 (16.1) | ||
| Risk factors, n (%) | ||||||
| Hypertension | 25 980 (74.9) | 5966 (78.4) | <0.001 | 5100 (79.2) | 5068 (78.6) | 0.425 |
| Diabetes mellitus | 13 832 (39.9) | 3202 (42.1) | <0.001 | 2724 (42.3) | 2713 (42.1) | 0.844 |
| Dyslipidemia | 17 100 (49.3) | 3446 (45.3) | <0.001 | 2902 (45.0) | 2956 (45.9) | 0.339 |
| Previous CVA/TIA | 7607 (21.9) | 2534 (33.3) | <0.001 | 2230 (34.6) | 2106 (32.7) | 0.021 |
| Heart disease | 7249 (20.9) | 2598 (34.1) | <0.001 | 2129 (33.0) | 2219 (34.4) | 0.094 |
| Atrial fibrillation | 896 (2.58) | 357 (4.69) | <0.001 | 279 (4.33) | 277 (4.30) | 0.931 |
| Ischemic heart disease | 3034 (8.75) | 1274 (16.7) | <0.001 | 1155 (17.9) | 1104 (17.1) | 0.237 |
| Congestive heart failure | 411 (1.19) | 181 (2.38) | <0.001 | 142 (2.20) | 142 (2.20) | 1.000 |
| Acute MI | 31 (0.09) | 27 (0.35) | <0.001 | 16 (0.25) | 22 (0.34) | 0.330 |
| Smoking | 12 834 (37.0) | 2531 (35.3) | <0.001 | 2148 (33.3) | 2213 (34.4) | 0.226 |
| Alcohol use | 4720 (13.6) | 764 (10.0) | <0.001 | 600 (9.31) | 657 (10.2) | 0.091 |
| UGI bleeding | 141 (0.41) | 442 (5.81) | <0.001 | 119 (1.85) | 173 (2.69) | 0.001 |
| mRS scores at discharge, n (%)d | ||||||
| 0 | 2417 (6.97) | 400 (5.24) | <0.001 | 343 (5.32) | 372 (5.77) | 0.022 |
| 1 | 8949 (25.8) | 1164 (15.3) | 1211 (18.8) | 1087 (16.9) | ||
| 2 | 7273 (21.0) | 1208 (15.9) | 1127 (17.5) | 1111 (17.2) | ||
| 3–5 | 16 040 (46.3) | 4839 (63.6) | 3762 (58.4) | 3873 (60.1) | ||
| NIHSS scores at discharge, n (%)e | ||||||
| <5 | 24 079 (69.4) | 4058 (53.3) | <0.001 | 3733 (57.9) | 3630 (56.3) | 0.001 |
| 5–19 | 9522 (27.5) | 2906 (38.2) | 2309 (35.8) | 2309 (35.8) | ||
| ≥20 | 1078 (3.11) | 647 (8.50) | 401 (6.22) | 504 (7.82) | ||
BMI indicates body mass index; CVA, cerebrovascular attack; LAA, large artery atherosclerosis; MI, myocardial infarction; mRS, modified Rankin Scale; NIHSS, National Institutes of Health Stroke Scale; PS, propensity score; SVD, small vessel disease; TIA, transient ischemic attack; TOAST, Trial of Org 10172 in Acute Stroke Treatment; UGI, upper gastrointestinal.
Before PS matching, the baseline characteristics of the 2 groups were significantly different (P<0.05) because of potential sampling bias (population ratio: aspirin/clopidogrel=5.05/1). After PS matching, there were no significant differences between the 2 groups for any variables.
The BMI is the weight in kilograms divided by the square of the height in meters.
Obesity was defined as a BMI of 27 or more.
Scores on the mRS ranged from 0 to 5, and higher scores indicated greater disability.
Higher scores on the NIHSS indicated greater stroke severity.