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

Exhibits 62 to 64

Exhibit 62. Results of logistic regression using the derivation dataset for only total hip surgery

Variable Estimate tValue Probability
Intercept -3.76 -1.01 0.3183
Age -0.02 -1.11 0.2674
Chronic lung disease 1.85 2.33 0.0197
Charlson score* -0.47 -1.07 0.2827
Emergency surgery 1.75 2.38 0.0172
General anesthesia 1.22 1.46 0.1447
Male 1.11 1.85 0.0645
Postop admission 3.55 3.36 0.0008
Preop glucose* -0.01 -0.46 0.6616
Preop hematocrit -0.03 -0.28 0.7829
Preop hemoglobin -0.25 -0.68 0.4966
Surgery duration 0.01 1.91 0.0571
Wound class 0.54 1.38 0.1681

*Additional Intermountain risk factor.

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Exhibit 63. Results of logistic regression using the validation dataset for only total hip surgery

Variable Estimate tValue Probability
Intercept -3.87 -1.34 0.1815
Age -0.01 -0.62 0.5327
Chronic lung disease 0.44 0.67 0.4999
Charlson score* 0.08 0.33 0.7412
Emergency surgery 0.95 1.18 0.2372
General anesthesia 1.12 1.44 0.1489
Male -0.78 -1.33 0.1842
Postop admission 1.37 2.63 0.0086
Preop glucose* -0.01 -1.22 0.2331
Preop hematocrit -0.06 -0.66 0.5089
Preop hemoglobin 0.13 0.46 0.6480
Surgery duration 0.01 1.75 0.0801
Wound class 0.26 0.49 0.6263

*Additional Intermountain risk factor.

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Exhibit 64. Results of logistic regression using the combined dataset for only total hip surgery

Variable Estimate tValue Probability
Intercept -3.87 -1.68 0.1005
Age -0.02 -1.23 0.2195
Chronic lung disease 1.07 2.32 0.0205
Charlson score* -0.14 -0.63 0.5271
Emergency surgery 1.31 2.60 0.0094
General anesthesia 1.03 1.87 0.0618
Male 0.11 0.28 0.7768
Postop admission 2.04 4.70 0.0000
Preop glucose* -0.01 -0.96 0.3454
Preop hematocrit -0.05 -0.78 0.4367
Preop hemoglobin -0.01 -0.03 0.9787
Surgery duration 0.01 2.94 0.0033
Wound class 0.34 1.13 0.2605

*Additional Intermountain risk factor.

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Page last reviewed December 2012
Internet Citation: Exhibits 62 to 64. December 2012. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/research/findings/final-reports/ssi/ssiexh62-64.html