Improving the Measurement of Surgical Site Infection Risk Stratification/Outcome Detection

Exhibits 38 to 40

Exhibit 38. Results of logistic regression using the derivation dataset for only total hip surgery

Variable Estimate tValue Probability
Intercept -3.15016 -1.31103 0.19127
Age -0.02436 -1.36677 0.17172
Chronic lung disease 0.717234 1.299857 0.19365
Emergency surgery 1.667783 2.711989 0.00669
No. of procedures 0.647188 2.857793 0.00442
Postop admission 1.502892 2.895868 0.00379
Postop hemoglobin -0.26253 -1.52152 0.12890
Preop hemoglobin 0.013404 0.231 0.82005
Surgery duration 0.007371 2.714224 0.00665

Postop = postoperative; Preop = preoperative.

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Exhibit 39. Results of logistic regression using the validation dataset for only total hip surgery

Variable Estimate tValue Probability
Intercept -5.30978 -2.3102 0.02089
Age -0.01718 -1.01601 0.30962
Chronic lung disease 1.181684 2.524745 0.01158
Emergency surgery 2.01501 3.420056 0.00063
No. of procedures -0.58576 -0.61154 0.54084
Postop admission 1.962564 3.988843 0.00007
Postop hemoglobin 0.079368 0.560087 0.72071
Preop hemoglobin 0.019021 0.361141 0.44228
Surgery duration 0.002467 1.890769 0.05866

Postop = postoperative; Preop = preoperative.

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Exhibit 40. Results of logistic regression using the combined dataset for only total hip surgery

Variable Estimate tValue Probability
Intercept -4.28495 -2.91129 0.00361
Age -0.02085 -1.74905 0.08028
Chronic lung disease 0.930147 2.645746 0.00815
Emergency surgery 1.730828 4.182002 0.00003
No. of procedures 0.410227 1.931115 1.931115
Postop admission 1.728514 4.971104 0.00000
Postop hemoglobin -0.09155 -0.89798 0.36925
Preop hemoglobin 0.014634 0.464605 0.64256
Surgery duration 0.003186 2.997669 0.00272

Postop = postoperative; Preop = preoperative.

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Page last reviewed December 2012
Internet Citation: Exhibits 38 to 40. December 2012. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/research/findings/final-reports/ssi/ssiexh38-40.html