Table 1. Baseline characteristics of study participants (before after propensity score 1∶1 matching).
| Variable | Before matching | After propensity matching | ||||||
| Aspirin users, (N = 2068) | Non-users, (N = 23272) | p-value | Standardized differences | Aspirin users, (N = 1884) | Non-users, (N = 1884) | p-value | Standardized differences | |
| Age, year | 61.7±13.0 | 48.5±15.7 | <0.001 | 1.269 | 61.0±13.0 | 61.5±13.6 | 0.180 | 0.046 |
| Male gender, n (%) | 1213 (58.7) | 11207 (48.2) | <0.001 | 0.212 | 1091 (57.9) | 1048 (55.6) | 0.164 | 0.046 |
| Diabetes, n (%) | 895 (43.3) | 3606 (15.5) | <0.001 | 0.641 | 769 (40.8) | 784 (41.6) | 0.630 | 0.016 |
| Hypertension, n (%) | 1369 (66.2) | 6285 (27.0) | <0.001 | 0.855 | 1203 (63.9) | 1244 (66.0) | 0.137 | 0.044 |
| BMI, kg/m2 | 25.3±5.6 | 25.3±6.1 | 0.881 | 0.006 | 25.4±5.6 | 25.4±5.8 | 0.116 | 0.001 |
| Previous CVD, n (%) | 718 (34.7) | 1082 (4.6) | <0.001 | 0.818 | 621 (33.0) | 579 (30.7) | 0.068 | 0.049 |
| Previous PUD, n (%) | 54 (2.6) | 1089 (4.7) | <0.001 | 0.112 | 53 (2.8) | 56 (3.0) | 0.847 | 0.012 |
| eGFR, ml/min/1.73 m2 | 42.3±28.1 | 69.8±29.3 | <0.001 | 1.283 | 43.2±28.7 | 43.7±26.4 | 0.544 | 0.025 |
| Proteinuria, n (%) | 1268 (61.3) | 10955 (47.1) | <0.001 | 0.288 | 1143 (60.7) | 1185 (62.9) | 0.261 | 0.045 |
| Laboratory | ||||||||
| Hemoglobin, g/dl | 12.3±2.6 | 13.2±2.2 | <0.001 | 0.282 | 12.3±2.6 | 12.2±2.7 | 0.640 | 0.015 |
| White blood cells, ×103/µl | 8.9±3.9 | 8.0±4.5 | <0.001 | 0.267 | 8.8±3.8 | 8.8±4.1 | 0.891 | 0.008 |
| Platelet, ×103/µl | 246.1±84.8 | 256.1±80.0 | <0.001 | 0.164 | 246.6±85.0 | 252.5±102.4 | 0.052 | 0.080 |
| Albumin, g/dl | 3.8±0.7 | 4.2±0.6 | <0.001 | 0.250 | 3.8±0.7 | 3.8±0.7 | 0.981 | 0.005 |
| Cholesterol, mg/dl | 193.2±60.3 | 188.3±47.3 | 0.004 | 0.112 | 193.1±60.3 | 192.4±59.1 | 0.854 | 0.017 |
| Triglycerides, mg/dl | 169.6±126.1 | 146.1±117.6 | <0.001 | 0.263 | 168.9±127.5 | 173.9±142.4 | 0.347 | 0.049 |
| HDL-cholesterol, mg/dl | 44.6±13.7 | 50.9±14.7 | <0.001 | 0.573 | 44.9±13.9 | 45.0±14.8 | 0.573 | 0.009 |
| Calcium, mg/dl | 8.9±0.8 | 9.1±0.7 | <0.001 | 0.106 | 8.9±0.9 | 8.9±0.8 | 0.615 | 0.014 |
| Phosphorus, mg/dl | 3.9±1.2 | 3.7±1.6 | <0.001 | 0.120 | 3.9±1.2 | 4.0±4.5 | 0.199 | 0.036 |
| Uric acid, mg/dl | 6.6±2.3 | 5.5±2.0 | <0.001 | 0.478 | 6.6±2.3 | 6.5±2.4 | 0.638 | 0.037 |
| Medications | ||||||||
| RAAS blockers, n (%) | 1443 (69.8) | 4973 (21.4) | <0.001 | 1.112 | 54 (2.9) | 64 (3.4) | 0.399 | 0.029 |
| Statin, n (%) | 813 (39.3) | 2563 (11.0) | <0.001 | 0.690 | 10 (0.5) | 21 (1.1) | 0.072 | 0.067 |
| Beta-blockers, n (%) | 1205 (58.3) | 3561 (15.3) | <0.001 | 0.996 | 37 (2.0) | 39 (2.1) | 0.907 | 0.020 |
| CCB, n (%) | 1275 (61.7) | 4385 (18.8) | <0.001 | 0.973 | 44 (2.3) | 55 (2.9) | 0.315 | 0.038 |
| Diuretics, n (%) | 1250 (60.4) | 4243 (18.2) | <0.001 | 0.958 | 65 (3.5) | 74 (3.9) | 0.488 | 0.021 |
| Warfarin, n (%) | 160 (7.7) | 370 (1.6) | <0.001 | 0.293 | 2 (0.1) | 0 (0) | 0.500 | 0.045 |
| Clopidogrel, n (%) | 287 (13.9) | 1084 (4.7) | <0.001 | 0.321 | 1 (0.1) | 6 (0.3) | 0.125 | 0.045 |
| Cilostazol, n (%) | 626 (30.3) | 662 (2.8) | <0.001 | 0.797 | 3 (0.2) | 2 (0.1) | >0.999 | 0.026 |
BMI: body mass index;
CVD: cardiovascular disease;
PUD: peptic ulcer disease;
eGFR: estimated glomerular filtration rate;
HDL: high-density lipoprotein;
RAAS: renin-angiotensin-aldosterone system;
CCB: calcium channel blocker.
Note: Conversion factors for units were as follows: hemoglobin in g/dl to g/l, ×10; white blood cell in ×103/µl to ×109/l, equal; platelets in ×103/µl to ×109/l, equal; albumin in mg/dl to g/l,×10; cholesterol in mg/dl to mmol/l,×0.02586; triglycerides in mg/dl to mmol/l,×0.01129; HDL-cholesterol in mg/dl to mmol/l,×0.02586; calcium in mg/dl to mmol/l, ×0.2495; phosphorus in mg/dl to mmol/l, ×0.3229; uric acid in mg/dl to µmol/l, ×59.48.