Table 1.
Baseline characteristics of patients and procedures.
| Control surveillance (n=148,365 procedures) | Intervention surveillance (n=89,339 procedures) | |||
|---|---|---|---|---|
| Number of unique patients | 129,997 | (88%) | 74,236 | (83%) |
| Age, yearsa | 55.9 | (17.8) | 56.5 | (17.7) |
| Sex | ||||
| Female | 81,139/129,997 | (6.4%) | 42,388/74,236 | (57.1%) |
| Male | 48,830/129,997 | (37.6%) | 31,843/74,236 | (42.9%) |
| Missing | 28/129,997 | (<0.1%) | 5/74,236 | (<0.1%) |
| Number of procedures per cluster | 850 | (402–1666) | 521 | (240–1574) |
| Procedure type | ||||
| Abdominal hysterectomy | 8953 | (6.0%) | 4836 | (5.4%) |
| Cardiac surgeryb | 1517 | (1.0%) | 1036 | (1.2%) |
| Coronary artery bypass graft | 3372 | (2.3%) | 1902 | (2.1%) |
| Carotid endarterectomy | 1209 | (0.8%) | 760 | (0.9%) |
| Cesarean section | 22,046 | (14.9%) | 10,827 | (12.1%) |
| Colon surgery | 7723 | (5.2%) | 8046 | (9.0%) |
| Herniorrhaphy | 21,141 | (14.2%) | 20,699 | (23.2%) |
| Hip prosthesis | 19,127 | (12.9%) | 8995 | (10.1%) |
| Knee prosthesis | 27,790 | (18.7%) | 12,571 | (14.1%) |
| Laminectomy | 15,526 | (10.5%) | 8520 | (9.5%) |
| Peripheral vascular bypass surgery | 677 | (0.5%) | 535 | (0.6%) |
| Spinal fusion | 16,078 | (10.8%) | 9540 | (10.7%) |
| Vaginal hysterectomy | 3206 | (2.2%) | 1072 | (1.2%) |
| NHSN risk index | ||||
| 0 | 59,641 | (40.2%) | 33,833 | (37.9%) |
| 1 | 73,600 | (49.6%) | 43,649 | (48.9%) |
| 2 | 14,542 | (9.8%) | 11,258 | (12.6%) |
| 3 | 582 | (0.4%) | 597 | (0.7%) |
| Missing | 0 | (0%) | 2 | (<0.1%) |
| ASA score | ||||
| 1 (no systemic disease) | 4969 | (3.3%) | 3385 | (3.8%) |
| 2 (mild systemic disease) | 68,079 | (45.9%) | 39,121 | (43.8%) |
| 3 (severe systemic disease, not life threatening) | 64,106 | (43.2%) | 39,899 | (44.7%) |
| 4 (severe systemic disease, life threatening) | 11,056 | (7.5%) | 6799 | (7.6%) |
| 5 (moribund patient) | 147 | (0.1%) | 122 | (0.1%) |
| Missing | 8 | (<0.1%) | 13 | (<0.1%) |
| Wound class | ||||
| Clean | 103,876 | (70.0%) | 58,559 | (65.5%) |
| Clean-contaminated | 41,290 | (27.8%) | 27,525 | (30.8%) |
| Contaminated | 1605 | (1.1%) | 1311 | (1.5%) |
| Dirty-infected | 1577 | (1.1%) | 1396 | (1.6%) |
| Missing | 17 | (<0.1%) | 548 | (0.6%) |
| Prolonged operative durationc | 25,939 | (17.5%) | 18,430 | (20.6%) |
Data are n (%), mean (SD), n/N (%), or median (IQR). ASA = American Society of Anesthesiologists. NHSN=National Healthcare Safety Network.
a
Age is given for unique patients. Missing data for age were excluded for 8 patients (6 patients who underwent procedures that received control surveillance and 2 patients who underwent procedures that received intervention surveillance).
b
Cardiac surgery included open chest procedures on the valves or septum of the heart.
c
Procedures were prolonged if the operative duration was longer than the NHSN 75th percentile benchmark.