Table 1.
Baseline characteristics of the study cohort.
| Variable | Female | Male | P–value |
|---|---|---|---|
| N = 418,885 | 247,561 | 171,324 | – |
| Demographic characteristics | |||
| Age (years) | 66.7 ± 10.2 | 65.2 ± 10.4 | <.0001 |
| Body mass index (kg/m2) | 32.2 ± 7.3 | 31.7 ± 6.0 | <.0001 |
| Current smoker | 22,580 (9.1%) | 19,532 (11.4%) | <.0001 |
| Chronic steroid use | 10,057 (4.1%) | 4853 (2.8%) | <.0001 |
| ASA classification | 2.4 ± 0.6 | 2.5 ± 0.6 | <.0001 |
| Race | |||
| White | 179,285 (82.7%)∗ | 127,460 (85.6%)∗ | <.0001 |
| Non-Hispanic black | 20,117 (9.3%)∗ | 10,952 (7.4%)∗ | |
| Hispanic | 10,325 (4.8%)∗ | 6548 (4.4%)∗ | |
| Asian | 5170 (2.4%)∗ | 2538 (1.7%)∗ | |
| Other minority race | 1793 (0.8%)∗ | 1468 (1.0%)∗ | |
| Functional status | <.0001 | ||
| Independent | 242,510 (98.5%) | 168,637 (98.9%) | |
| Partially or completely dependent | 3793 (1.5%) | 1820 (1.1%) | |
| Preoperative living environment | <.0001 | ||
| Admitted directly from home | 246,572 (99.7%) | 170,778 (99.8%) | |
| Admitted from a facility | 784 (0.3%) | 379 (0.2%) | |
| Comorbidity characteristics | |||
| Diabetes | 36,276 (14.7%) | 29,466 (17.2%) | <.0001 |
| Hypertension | 151,014 (61.0%) | 107,435 (62.7%) | <.0001 |
| Chronic obstructive pulmonary disease | 9149 (3.7%) | 6059 (3.5%) | .007 |
| Chronic heart failure | 569 (0.2%) | 557 (0.3%) | <.0001 |
| Anemia | 28,584 (12.1%) | 45,015 (27.5%) | <.0001 |
| Metastatic cancer | 294 (0.1%) | 227 (0.1%) | .215 |
| Bleeding disorder | 4083 (1.7%) | 4742 (2.8%) | <.0001 |
| Dyspnea | 14,691 (5.9%) | 7749 (4.5%) | <.0001 |
| Ascites | 33 (0.0%) | 36 (0.0%) | .057 |
| Chronic kidney disease | 3825 (1.6%) | 6830 (4.3%) | <.0001 |
| Perioperative characteristics | |||
| Procedure type | |||
| Total hip arthroplasty (THA) | 85,179 (34.4%) | 70,712 (41.3%) | <.0001 |
| Total knee arthroplasty (TKA) | 162,382 (65.6%) | 100,612 (58.7%) | |
| Diagnosis | <.0001 | ||
| Primary osteoarthritis | 80,861 (94.9%)∗ | 65,621 (92.8%)∗ | |
| Inflammatory arthritis | 418 (0.5%)∗ | 145 (0.2%)∗ | |
| Posttraumatic arthritis | 366 (0.4%)∗ | 542 (0.8%)∗ | |
| Childhood dysplasia (THA only) | 628 (0.7%)∗ | 287 (0.4%)∗ | |
| Osteonecrosis (THA only) | 2906 (3.4%)∗ | 4117 (5.8%)∗ | |
| Bilateral procedure | 4523 (1.8%) | 3656 (2.1%) | <.0001 |
| Procedure length (minutes) > 100 | 71,084 (28.7%) | 61,041 (35.6%) | <.0001 |
ASA, American Society of Anesthesiologists physical classification system.
Values are presented as the mean and standard deviation (continuous variables) or as the frequency and percentage (nominal variables). P–values indicate significant overall differences between patient groups and are determined using a chi-squared test (nominal variables) or Welch’s t-test (continuous variables).
An asterisk indicates attribution of the overall significance to the respective variable category, as determined using adjusted residuals.
Bold indicates statistical significance.