Table 5 Comparison of baseline characteristics by surgical site infection status pre- and post-match in the total knee arthroplasty cohort
From: Economic burden of surgical site infections within the episode of care following joint replacement
| Â | Â | Pre-match | Â | Post-match |
|---|---|---|---|---|
Total | No SSI | SSI | no SSI | |
N | 158,516 | 157,376 | 1140 | 1140 |
Mean age (SD) | 66.25 (9.7) | 66.3 (9.7) | 65.3 (10.0) | 65.8 (9.7) |
Sex (%) | ||||
 Male | 61,012 (38.5) | 60,456 (38.4) | 556 (48.8) | 562 (49.3) |
 Female | 97,504 (61.5) | 96,920 (61.6) | 584 (51.2) | 578 (50.7) |
Payer (%) | ||||
 Medicare | 90,700 (57.2) | 90,040 (57.2) | 660 (57.9) | 672 (59.0) |
 Medicaid | 4607 (2.9) | 4535 (2.9) | 72 (6.3) | 69 (6.1) |
 Private insurance | 55,590 (35.1) | 55,243 (35.1) | 347 (30.4) | 349 (30.6) |
 Self-pay | 636 (0.4) | 626 (0.4) | 10 (0.9) | 15 (1.3) |
 No charge | 166 (0.1) | 163 (0.1) | 3 (0.3) | 4 (0.4) |
 Other | 6632 (4.2) | 6585 (4.2) | 47 (4.1) | 31 (2.7) |
 Unknown | 185 (0.1) | 184 (0.1) | 1 (0.1) | 0(0) |
Hospital bedsize (%) | ||||
 Small | 28,404 (17.9) | 28,223 (17.9) | 181 (15.9) | 172 (15.1) |
 Medium | 42,309 (26.7) | 41,997 (26.7) | 312 (27.4) | 298 (26.1) |
 Large | 87,803 (55.4) | 87,156 (55.4) | 647 (56.8) | 670 (58.8) |
Zip income quartile (%) | Â | |||
 0–25th percentile | 33,248 (21.0) | 32,992 (21.0) | 256 (22.5) | 268 (23.5) |
 26th–50th percentile | 42,535 (26.8) | 42,237 (26.8) | 298 (26.1) | 286 (25.1) |
 51st–75th percentile | 43,118 (27.2) | 42,810 (27.2) | 308 (27.0) | 312 (27.4) |
 76th–100th percentile | 37,061 (23.4) | 36,799 (23.4) | 262 (23.0) | 264 (23.2) |
 Unknown | 2554 (1.6) | 2538 (1.6) | 16 (1.4) | 10 (0.9) |
Hospital teaching status (%) | ||||
 Metropolitan non-teaching | 78,155 (49.3) | 77,586 (49.3) | 569 (49.9) | 581 (51.0) |
 Metropolitan teaching | 64,844 (40.9) | 64,391 (40.9) | 453 (39.7) | 461 (40.4) |
 Non-metropolitan teaching | 15,517 (9.8) | 15,399 (9.8) | 118 (10.4) | 98 (8.6) |
Comorbidity Index (%) | ||||
 0–1 | 124,721 (78.7) | 123,890 (78.7) | 831 (72.9) | 833 (73.1) |
 2–3 | 12,378 (7.8) | 12,273 (7.8) | 105 (9.2) | 100 (8.8) |
 > 3 | 21,417 (13.5) | 21,213 (13.5) | 204 (17.9) | 207 (18.2) |