Table 1.
Distribution of patient characteristics and missing data among the general anesthesia and spinal anesthesia groups. Values are frequency (%) unless otherwise stated
| Factor | Spinal anesthesia (n = 2,279) | Missing data (%) | General anesthesia (n = 1,630) | Missing data (%) | Cumulative missing data (%) |
|---|---|---|---|---|---|
| Age, mean (SD) | 70 (9.5) | 0 | 67 (10) | 0 | 0 |
| Male sex | 789 (35) | 0 | 597 (37) | 0 | 0 |
| BMI, mean (SD) | 28.7 (4.7) | 0 | 29.7 (5.2) | 2 (0.1) | 2 (0.0) |
| ASA 1 | 348 (15) | 0 | 221 (14) | 1 (0.1) | 1 (0.0) |
| ASA 2 | 1,614 (71) | 0 | 1,049 (64) | 1 (0.1) | 1 (0.0) |
| ASA 3 | 306 (13) | 0 | 344 (21) | 1 (0.1) | 1 (0.0) |
| ASA 4 | 11 (0.5) | 0 | 15 (0.9) | 1 (0.1) | 1 (0.0) |
| Active smoker | 231 (11) | 101 (4.4) | 223 (14) | 61 (3.7) | 162 (4.1) |
| TKA | 1,082 (48) | 0 | 716 (44) | 0 | 0 |
| 2014 | 674 (30) | 0 | 286 (18) | 0 | 0 |
| 2015 | 591 (26) | 0 | 391 (24) | 0 | 0 |
| 2016 | 488 (21) | 0 | 518 (32) | 0 | 0 |
| 2017 | 526 (23) | 0 | 435 (27) | 0 | 0 |
| Mean surgery duration, min (SD) | 59 (16) | 0 | 62 (16) | 0 | 0 |
| Hypothermia | 87 (5.6) | 724 (32) | 54 (3.8) | 223 (14) | 947 (24) |
| PJI | 19 (0.8) | 0 | 28 (1.7) | 0 | 0 |
Percentages are displayed as valid (calculated through discarding missing data) percentages.
BMI: body mass index,
TKA: total knee arthroplasty,
PJI: periprosthetic joint infection.