Table 2.
Descriptive characteristics of propensity score matched total hip replacement (THR) patients according to red blood cell transfusion within 8 days of surgery.
| Transfusion n = 2,254 | No transfusion n = 2,254 | Standardized mean difference*** | |
|---|---|---|---|
| Age (years) | |||
| 10-49 | 146 (6.5%) | 159 (7.1%) | 0.07561 |
| 50-59 | 272 (12.1%) | 256 (11.4%) | 0.03827 |
| 60-69 | 602 (26.7%) | 635 (28.2%) | 0.07124 |
| 70-79 | 830 (36.8%) | 793 (35.2%) | 0.00596 |
| +80 | 404 (17.9%) | 411 (18.2%) | 0.18397 |
| Sex | |||
| Female | 1,490 (66.1%) | 1,439 (63.8%) | 0.11293 |
| Primary hip diagnosis | |||
| Primary arthrosis | 1,647 (73.1%) | 1,633 (72.5%) | 0.23293 |
| Trauma | 323 (14.3%) | 319 (14.2%) | 0.28662 |
| Other | 284 (12.6%) | 302 (13.4%) | 0.00682 |
| Comorbidity history (yes) | |||
| Myocardial infarction | 104 (4.6%) | 113 (5.0%) | 0.02865 |
| Congestive heart failure | 116 (5.2%) | 125 (5.6%) | 0.08273 |
| Peripheral vascular disease | 97 (4.3%) | 95 (4.2%) | 0.02495 |
| Cerebrovascular disease | 172 (7.6%) | 172 (7.6%) | 0.11255 |
| Dementia | 15 (0.7%) | 8 (0.4%) | 0.10249 |
| Chronic pulmonary disease | 192 (8.5%) | 176 (7.8%) | 0.06104 |
| Connective tissue disease | 169 (7.5%) | 161 (7.1%) | 0.02309 |
| Peptic ulcer disease | 129 (5.7%) | 129 (5.7%) | 0.07967 |
| Mild liver disease | 37 (1.6%) | 30 (1.3%) | 0.04168 |
| Diabetes (type I and II) | 134 (5.9%) | 115 (5.1%) | 0.05238 |
| Hemiplegia | 4 (0.2%) | 6 (0.3%) | 0.03791 |
| Moderate to severe renal disease | 55 (2.4%) | 60 (2.7%) | 0.06410 |
| Diabetes with end organ damage | 61 (2.7%) | 47 (2.1%) | 0.06301 |
| Any tumor | 260 (11.5%) | 235 (10.4%) | 0.09151 |
| Leukemia | 10 (0.4%) | 6 (0.3%) | 0.04010 |
| Lymphoma | 18 (0.8%) | 14 (0.6%) | 0.04218 |
| Moderate to severe liver disease | 11 (0.5%) | 12 (0.5%) | 0.03710 |
| Metastatic solid tumor | 39 (1.7%) | 26 (1.2%) | 0.08036 |
| Fixation technique | |||
| Cemented | 1,186 (52.6%) | 1,175 (52.1%) | 0.03568 |
| Cementless | 523 (23.2%) | 522 (23.2%) | 0.05074 |
| Hybrid | 545 (24.2%) | 557 (24.7%) | 0.01191 |
| Type of anesthesia | |||
| Regional | 1,753 (77.8%) | 1,757 (78.0%) | 0.18378 |
| Duration of surgery (minutes) | |||
| 0-60 | 418 (18.5%) | 426 (18.9%) | 0.09806 |
| 61-120 | 1,685 (74.8%) | 1671 (74.1%) | 0.03567 |
| >121 | 151 (6.7%) | 157 (7.0%) | 0.20997 |
| 20 hospitals performing the THR procedures* | |||
| Prophylaxis for heterotopic bone formation ** | |||
| Yes | 195 (8.7%) | 208 (9.2%) | 0.06109 |
| No | 2059 (91.4%) | 2046 (90.7%) | 0.06268 |
| Preoperative Hemoglobin concentration within three months prior to surgery | |||
| <138.5 g/L | 1410 (62.6%) | 1362 (60.4%) | 0.25041 |
| >138.5 g/L | 844 (37.4%) | 892 (39.6%) | 0.25041 |
| Year of surgery | |||
| 1999 | 61 (2.7%) | 58 (2.6% | 0.03572 |
| 2000 | 60 (2.7%) | 56 (2.5%) | 0.06520 |
| 2001 | 94 (4.2%) | 93 (4.1%) | 0.02234 |
| 2002 | 309 (13.7%) | 333 (14.8%) | 0.02030 |
| 2003 | 239 (10.6%) | 254 (11.3% | 0.00876 |
| 2004 | 377 (16.7%) | 392 (17.4%) | 0.04756 |
| 2005 | 347 (15.4%) | 333 (14.8%) | 0.01024 |
| 2006 | 435 (19.3%) | 411 (18.2%) | 0.01185 |
| 2007 | 332 (14.7%) | 324 (14.4%) | 0.00976 |
Data are shown in number (%) unless otherwise specified. *Good balance between groups for each of the 20 hospitals included in the propensity score was achieved in general. ** Anti -rheumatic drugs were used as prophylaxis for heterotopic bone formation. *** A standardized mean difference that exceeds 0.1 is indicative of significant imbalance between groups.