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

Exhibits 35 to 37

Exhibit 35. Results of logistic regression using the derivation dataset for only herniorrhaphy

Variable Estimate tValue Probability
Intercept -7.19702 -2.90005 0.00378
No. of procedures -1.22262 -1.19116 0.23359
Postop admission 2.105654 3.434398 0.00059
Postop hematocrit -0.15235 -2.04515 0.04164
Postop hemoglobin 0.558391 2.282273 0.02329
Longer preoperative stay 0.119229 1.583554 0.11330
History of rheumatism 1.80024 1.428812 0.15310
Wound class 0.812588 1.409284 0.15876

Postop = postoperative; Preop = preoperative.

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Exhibit 36. Results of logistic regression using the validation dataset for only herniorrhaphy

Variable Estimate tValue Probability
Intercept -6.63084 -3.1182 0.00195
No. of procedures 0.389846 1.706724 0.08789
Postop admission 3.430942 5.136659 0.00000
Postop hematocrit 0.132635 1.271441 0.20613
Postop hemoglobin -0.42173 -1.32403 0.18974
Longer preoperative stay 0.006993 0.13405 0.89336
History of rheumatism 0.632211 0.536855 0.59137
Wound class 0.407113 0.76837 0.44228

Postop = postoperative; Preop = preoperative.

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Exhibit 37. Results of logistic regression using the combined dataset for only herniorrhaphy

Variable Estimate tValue Probability
Intercept -6.53827 -4.0998 0.00007
No. of procedures 0.174594 0.920322 0.35743
Postop admission 2.787336 6.551838 0.00000
Postop hematocrit -0.03547 -0.44784 0.66071
Postop hemoglobin 0.082922 0.331393 0.74535
Longer preoperative stay 0.036602 1.854843 0.06362
History of rheumatism 1.226935 1.51136 0.13070
Wound class 0.490776 1.44229 0.14923

Postop = postoperative; Preop = preoperative.

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Page last reviewed December 2012
Page originally created December 2012
Internet Citation: Exhibits 35 to 37. Content last reviewed December 2012. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/research/findings/final-reports/ssi/ssiexh35-37.html