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

Exhibits 68 to 70

Exhibit 68. Results of logistic regression using the derivation dataset for only appendectomy surgeries

Variable Estimate tValue Probability
Intercept -2.31 -0.88 0.3806
Age 0.01 1.12 0.2634
Charlson score* 0.20 1.96 0.0496
Diabetes -1.07 -1.12 0.2646
General anesthesia -1.25 -0.82 0.4100
History of MRSA 1.51 1.32 0.1860
Postop admission 2.21 4.56 0.0000
Postop hematocrit -0.14 -2.00 0.0478
Postop hemoglobin 0.27 1.02 0.3178
Preop glucose* 0.01 0.99 0.3222
Preop hemoglobin -0.16 -0.68 0.5045

*Additional Intermountain risk factor.

Return to Document

Exhibit 69. Results of logistic regression using the validation dataset for only appendectomy surgeries.

Variable Estimate tValue Probability
Intercept -4.95 -1.27 0.2050
Age -0.01 -0.21 0.8311
Charleson score* -0.32 -0.78 0.4367
Diabetes 1.90 1.24 0.2134
General anesthesia@      
History of MRSA@      
Postop admission 2.40 2.92 0.0035
Postop hematocrit -0.28 -2.09 0.0392
Postop hemoglobin 0.84 2.06 0.0434
Preop glucose* -0.01 -0.92 0.3632
Preop hemoglobin -0.09 -0.31 0.7564

@No patients in this dataset had the specific risk factor and no probability could be calculated.
*Additional Intermountain risk factor.

Return to Document

Exhibit 70. Results of logistic regression using the combined dataset for only appendectomy surgeries

Variable Estimate tValue Probability
Intercept -3.34 -1.48 0.1399
Age 0.01 1.01 0.3142
Charlson score* 0.16 1.65 0.0995
Diabetes -0.62 -0.79 0.4299
General anesthesia -1.72 -1.33 0.1823
History of MRSA 0.97 0.89 0.3710
Postop admission 2.27 5.43 0.0000
Postop hematocrit -0.13 -2.24 0.0263
Postop hemoglobin 0.40 2.15 0.0317
Preop glucose* 0.00 0.65 0.5150
Preop hemoglobin -0.16 -0.97 0.3379

*Additional Intermountain risk factor.

Return to Document

Page last reviewed December 2012
Page originally created December 2012
Internet Citation: Exhibits 68 to 70. Content last reviewed December 2012. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/research/findings/final-reports/ssi/ssiexh68-70.html