Exhibit 29. Results of logistic regression using the 60-percent derivation set, including each of the five surgical procedures as a possible risk factor
| Variable | Estimate | tValue | Probability |
|---|---|---|---|
| Intercept | -5.66922 | -7.18334 | 0.00000 |
| Admission transfer | 0.249358 | 0.655373 | 0.51223 |
| History of cancer | 0.675356 | 1.234336 | 0.21708 |
| Chronic kidney disease | -2.28736 | -2.24028 | 0.02507 |
| General anesthesia | 0.419425 | 1.499021 | 0.13387 |
| Male | 0.58722 | 2.677562 | 0.00742 |
| History of MRSA | 1.47331 | 4.87133 | 0.00000 |
| Number of procedures | 0.381148 | 3.171798 | 0.00151 |
| Postop admission | 2.104624 | 9.115523 | 0.00000 |
| Postop hematocrit | -0.04406 | -2.01137 | 0.04496 |
| Preop stay | 0.042437 | 1.623837 | 0.10441 |
| CABG surgery | 0.24496 | 0.746911 | 0.45512 |
| Herniorrhaphy | 0.186762 | 0.564969 | 0.57209 |
| Wound class | 0.003031 | 0.014814 | 0.98818 |
CABG = coronary artery bypass grafting; MRSA = methicillin-resistant Staphylococcus aureus; Postop = postoperative; Preop = preoperative.
Exhibit 30. Results of logistic regression using the 40-percent validation set, including each of the five surgical procedures as a possible risk factor
| Variable | Estimate | tValue | Probability |
|---|---|---|---|
| Intercept | -5.9448 | -7.7606 | 0.00000 |
| Admission transfer | -0.46026 | -0.92513 | 0.35490 |
| History of cancer | -0.78305 | -0.76388 | 0.44494 |
| Chronic kidney disease | -0.49964 | -0.91168 | 0.36193 |
| General anesthesia | 0.046769 | 0.171229 | 0.86404 |
| Male | -0.08612 | -0.3914 | 0.69550 |
| History of MRSA | 1.149853 | 3.048832 | 0.00230 |
| Number of procedures | 0.264643 | 1.861373 | 0.06269 |
| Postop admission | 2.115295 | 9.348542 | 0.00000 |
| Postop hematocrit | -0.01706 | -0.79509 | 0.42677 |
| Preop stay | 0.035891 | 1.814288 | 0.06963 |
| CABG surgery | 0.725095 | 2.077166 | 0.03779 |
| Herniorrhaphy | 0.553825 | 1.787663 | 0.07383 |
| Wound class | 0.326074 | 1.904355 | 0.05686 |
CABG = coronary artery bypass grafting; MRSA = methicillin-resistant Staphylococcus aureus; Postop = postoperative; Preop = preoperative.
Exhibit 31. Results of logistic regression using the combined derivation and validation sets, including each of the five surgical procedures as a possible risk factor
| Variable | Estimate | tValue | Probability |
|---|---|---|---|
| Intercept | -5.75478 | -10.6587 | 0.00000 |
| Admission transfer | -0.07527 | -0.25258 | -0.25258 |
| History of cancer | 0.186484 | 0.396676 | 0.69161 |
| Chronic kidney disease | -1.19328 | -2.52852 | 0.01145 |
| General anesthesia | 0.248213 | 1.277382 | 0.20147 |
| Male | 0.254338 | 1.658706 | 0.09718 |
| History of MRSA | 1.347607 | 5.798036 | 0.00000 |
| Number of procedures | 0.322013 | 3.494699 | 0.00047 |
| Postop admission | 2.111179 | 13.10889 | 0.00000 |
| Postop hematocrit | -0.03231 | -2.16588 | 0.03045 |
| Preop stay | 0.035145 | 2.315832 | 0.02057 |
| CABG surgery | 0.477163 | 2.015653 | 0.04384 |
| Herniorrhaphy | 0.376815 | 1.673907 | 0.09415 |
| Wound class | 0.16983 | 1.300158 | 0.19355 |
CABG = coronary artery bypass grafting; MRSA = methicillin-resistant Staphylococcus aureus; Postop = postoperative; Preop = preoperative.
