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Does the Centers for Disease Control’s NNIS System Risk Index Stratify Patients Undergoing Cardiothoracic Operations by Their Risk of Surgical-Site Infection?

Published online by Cambridge University Press:  02 January 2015

Marie-Claude Roy ,
Loreen A. Herwaldt ,
Richard Embrey ,
Kristen Kuhns ,
Richard P. Wenzel  and
Trish M. Perl
Marie-Claude Roy
Affiliation:
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa
Loreen A. Herwaldt*
Affiliation:
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa University of Iowa Hospitals and Clinics, Iowa City, Iowa
Richard Embrey
Affiliation:
Department of Surgery, University of Iowa College of Medicine, Iowa City, Iowa
Kristen Kuhns
Affiliation:
University of Iowa Hospitals and Clinics, Iowa City, Iowa
Richard P. Wenzel
Affiliation:
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa
Trish M. Perl
Affiliation:
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa
*
Department of Internal Medicine, The University of Iowa Hospitals and Clinics, 200 Hawkins Dr, Iowa City, IA 52242-1081
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Abstract

Background:

In 1991, the Centers for Disease Control and Prevention devised the National Nosocomial Infection Surveillance (NNIS) System risk index to stratify populations of surgical patients by the risk of acquiring surgical-site infections (SSIs).

Objective:

To determine whether the NNIS risk index adequately stratifies a population of cardiothoracic surgery patients by the risk of developing SSI.

Design:

Casecontrol study.

Setting:

The University of Iowa Hospitals and Clinics, a 900-bed, midwestern, tertiary-care hospital.

Patients:

201 patients with SSIs identified by prospective infection control surveillance and 398 controls matched by age, gender, type of procedure, and date of procedure. All patients underwent cardiothoracic operative procedures between November 1990 and January 1994.

Results:

The SSI rate was 7.8%. Seventy-four percent of cases and 80% of controls had a NNIS risk index score of 1; 24% of cases and 16% of controls had a score of 2 (P=.05). Patients with a NNIS risk score ≥2 were 1.8 times more likely to develop an SSI than those with a NNIS score <2 (odds ratio, 1.83; 95% confidence interval, 1.14-2.94, P=.01). The duration of the procedure was the only component of the index that stratified the population by risk of SSI.

Conclusions:

The risk of SSI after cardiothoracic operations increases as the NNIS risk index score increases. However, this index only dichotomized the patient population on the basis of the procedure duration. More research is needed to develop a risk index that adequately stratifies the risk of SSI after cardiothoracic operations.

Type
Original Articles
Information
Infection Control & Hospital Epidemiology , Volume 21 , Issue 3 , March 2000 , pp. 186 - 190
Copyright
Copyright © The Society for Healthcare Epidemiology of America 2000

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