Table 1. Baseline characteristics of patients with hip and knee replacement.
| Parameters | Patients with knee replacement | Patients with knee replacement | ||||
|---|---|---|---|---|---|---|
| Chemoprophylaxis (-) (n = 13,868) |
Chemoprophylaxis (+) (n = 8,259) |
P value* | Chemoprophylaxis (-) (n = 27,305) |
Chemoprophylaxis (+) (n = 25,577) |
P value* | |
| No. (%) | No. (%) | No. (%) | No. (%) | |||
| Gender | 0.001 | 0.001 | ||||
| Male | 5,445 (39.3) | 3,052 (37.0) | 3,553 (13.0) | 2,927 (11.4) | ||
| Female | 8,423 (60.7) | 5,207 (63.0) | 23,752 (87.0) | 22,650 (88.6) | ||
| Age (yr)‡ | ||||||
| Mean ± SD | 68.6±15.2 | 69.6±14.2 | <0.001 | 68.5±7.7 | 68.6±7.0 | 0.333 |
| ≤ 44 | 1,145 (8.3) | 547 (6.6) | <0.001† | 141 (0.5) | 36 (0.1) | <0.001† |
| 45 ≤ age ≤ 64 | 3,433 (24.8) | 1,900 (23.0) | 7,070 (25.9) | 6,595 (25.8) | ||
| 65 ≤ age ≤ 74 | 3,456 (24.9) | 2,254 (27.3) | 14,222 (52.1) | 13,860 (54.2) | ||
| 75 ≤ age ≤ 84 | 4,077 (29.4) | 2,572 (31.1) | 5,700 (20.9) | 4,939 (19.3) | ||
| ≥ 85 | 1,757 (12.7) | 986 (11.9) | 172 (0.6) | 147 (0.6) | ||
| Past medical history | ||||||
| Venous thromboembolic event (<3 yr) | 317 (2.3) | 308 (3.7) | < 0.001 | 644 (2.4) | 759 (3.0) | < 0.001 |
| Surgical site infection (<3 yr) | 536 (3.9) | 328 (4.0) | 0.693 | 487 (1.8) | 424 (1.7) | 0.267 |
| Diabetes (<3 yr) | 5,600 (40.4) | 3,622 (43.9) | < 0.001 | 12,172 (44.6) | 11,817 (46.2) | < 0.001 |
| Stroke (<3 yr) | 2,534 (18.3) | 1,746 (21.1) | < 0.001 | 3,449 (12.6) | 3,216 (12.6) | 0.842 |
| Renal disease (<3 yr) | 800 (5.8) | 567 (6.9) | 0.001 | 1,305 (4.8) | 1,253 (4.9) | 0.522 |
| Hypertension (<3 yr) | 7,912 (57.1) | 5,322 (64.4) | < 0.001 | 18,691 (68.5) | 18,551 (72.5) | < 0.001 |
| Coronary artery stenosis ( < 3 yr) | 2,819 (20.3) | 2,216 (26.8) | <0.001 | 6,545 (24.0) | 6,683 (26.1) | < 0.001 |
| Chronic heart failure, congestive heart failure (<3 yr) | 1,012 (7.3) | 794 (9.6) | < 0.001 | 2,003 (7.3) | 1,819 (7.1) | 0.321 |
| Arrhythmia (<3 yr) | 828 (6.0) | 629 (7.6) | < 0.001 | 1,862 (6.8) | 1,900 (7.4) | 0.007 |
| Atrial fibrillation ( < 3 yr) | 455 (3.3) | 486 (5.9) | < 0.001 | 736 (2.7) | 750 (2.9) | 0.100 |
| Malignancy (≤3 yr) | 1,616 (11.7) | 970 (11.7) | 0.837 | 2,230 (8.2) | 2,043 (8.0) | 0.450 |
| Varicose vein (<3 yr) | 127 (0.9) | 99 (1.2) | 0.043 | 708 (2.6) | 724 (2.8) | 0.092 |
| Hormone therapy (≤1 yr) | 368 (2.7) | 247 (3.0) | 0.140 | 892 (3.3) | 857 (3.4) | 0.590 |
| Anticoagulation therapy (<6 mo) | 751 (5.4) | 718 (8.7) | < 0.001 | 1,109 (4.1) | 1,386 (5.4) | < 0.001 |
| Surgical characteristics | ||||||
| Hospital pattern (level of reference) | <0.001 | <0.001 | ||||
| Tertiary general hospital | 2,569 (18.5) | 2,890 (35.0) | 3,259 (11.9) | 3,320 (13.0) | ||
| General hospital | 6,209 (44.8) | 3,444 (41.7) | 7,176 (26.3) | 6,382 (25.0) | ||
| Hospital | 4,798 (34.6) | 1,887 (22.8) | 15,336 (56.2) | 15,407 (60.2) | ||
| Clinic | 292 (2.1) | 38 (0.5) | 1,534 (5.6) | 468 (1.8) | ||
| Type of surgery | <0.001† | <0.001† | ||||
| HRA: Primary bipolar hip hemiarthroplasty | 8,256 (59.5) | 4,399 (53.3) | ||||
| HRA: Primary total hip arthroplasty | 4,248 (30.6) | 2,904 (35.2) | ||||
| HRA: Revision partial hip arthroplasty | 508 (3.7) | 364 (4.4) | ||||
| HRA: Revision total hip arthroplasty | 856 (6.2) | 592 (7.2) | ||||
| KRA: Primary unicompartmental knee arthroplasty | 735 (2.7) | 580 (2.3) | ||||
| KRA: Unilateral primary total knee arthroplasty | 15,784 (57.8) | 12,869 (50.3) | ||||
| KRA: Bilateral primary total knee arthroplasty | 9,600 (35.2) | 11,169 (43.7) | ||||
| KRA: Revision partial knee arthroplasty | 364 (1.3) | 334 (1.3) | ||||
| KRA: Revision total knee arthroplasty | 822 (3.0) | 625 (2.4) | ||||
| Anesthesia§ | <0.001† | <0.001† | ||||
| Regional anesthesia | 11,209 (80.8) | 6,450 (78.1) | 24,512 (89.8) | 23,744 (92.8) | ||
| General anesthesia | 2,659 (19.2) | 1,809 (21.9) | 2,793 (10.2) | 1,833 (7.2) | ||
| RBC transfusion (unit) | ||||||
| Mean±SD | 3.5±2.8 | 4.0±3.1 | <0.001 | 3.5±2.1 | 4.3±2.7 | <0.001 |
| 0 | 2,198 (15.8) | 1,205 (14.6) | <0.001† | 5,498 (20.1) | 3,782 (14.8) | <0.001† |
| 0<RBC≤3 | 7,520 (54.2) | 3,792 (45.9) | 12,948 (47.4) | 9,918 (38.8) | ||
| >3 | 4,150 (29.9) | 3,262 (39.5) | 8,859 (32.4) | 11,877 (46.4) | ||
| Platelet transfusion (unit) | ||||||
| Mean±SD | 8.7±13.7 | 7.4±11.2 | 0.728 | 6.3±8.9 | 6.1±9.7 | <0.001 |
| 0 | 12,802 (92.3) | 7,535 (91.2) | <0.001† | 26,612 (97.5) | 25,110 (98.2) | <0.001† |
| 0<Platelet concentrate≤3 | 521 (3.8) | 341 (4.1) | 389 (1.4) | 263 (1.0) | ||
| 3<Platelet concentrate≤10 | 293 (2.1) | 246 (3.0) | 190 (0.7) | 141 (0.6) | ||
| >10 | 252 (1.8) | 137 (1.7) | 114 (0.4) | 63 (0.2) | ||
| Duration of anesthesia (hr)∥ | ||||||
| Mean±SD | 2.9±2.0 | 3.0±2.1 | 0.242 | 2.9±1.7 | 2.7±1.7 | <0.001 |
| <2.5 | 2,188 (15.8) | 1,223 (14.8) | 0.005† | 3,124 (11.4) | 3,994 (15.6) | <0.001† |
| 2.5≤duration<4 | 6,845 (49.4) | 4,262 (51.6) | 9,843 (36.0) | 7,912 (30.9) | ||
| ≥4 | 4,810 (34.7) | 2,767 (33.5) | 14,044 (51.4) | 13,660 (53.4) | ||
†Independent t-test for continuous variables; †Chi-square test or Fisher's exact test for categorical variables; ‡Age at Index date of arthroplasty; §Defined as general anesthesia if inhalant was used; ∥No record of anesthesia duration : hip (n=32), Knee (n=305).