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INFORMATION IN PRACTICE: A P R Wilson, C Gibbons, B C Reeves, B Hodgson, M Liu, D Plummer, Z H Krukowski, J Bruce, J Wilson, and A Pearson Surgical wound infection as a performance indicator: agreement of common definitions of wound infection in 4773 patients BMJ 2004; 0: bmj.38232.646227.DEv1 [Abstract]

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Surgical wound infection as a performance indicator: lack of methodological detail prevents interpretation

Emily S Petherick, Nicky Cullum, and J Martin Bland   (15 October 2004)

Surgical wound infection as a performance indicator: lack of methodological detail prevents interpretation 15 October 2004
Emily S Petherick, Research Fellow Department of Health Sciences, University of York, York YO10 5DD, Nicky Cullum, and J Martin Bland Send response to journal: Re: Surgical wound infection as a performance indicator: lack of methodological detail prevents interpretation	The paper by Wilson and colleagues[1] promised a great deal in its title, but methodological brevity reduced readers’ ability to make use of its content. It is not surprising that the CDC, NINSS, ASEPSIS and Cruse definitions of wound infection perform differently. The NINSS definition is basically the CDC definition with slight modifications, hence the agreement between them was higher than with the ASEPSIS score. Furthermore, ASEPSIS (unlike the others) was conceived as a means of scoring the condition of surgical wounds rather than diagnosing infection, and data supporting the cut-point of 20 were not presented or referenced. Choice of cut-point will clearly affect agreement between ASEPSIS and comparators and in this case a score of 20 points on ASEPSIS resulted in a lower rate of infected wounds than the other definitions. We are told nothing of the clinical significance of the wounds detected using these methods so we are unable to tell which method of classification is best at discriminating between clinically significant and non-significant wounds. The fact that ASEPSIS incorporates length of stay as a dimension[2] may mean that it better identifies clinically important infections but the data to support this are not there. Furthermore the description of methods in the report is too vague and often ambiguous to permit interpretation and replication. How did the surveillance staff collect data? Did they collect relevant data from patients, staff and notes (were all these sources required for each assessment?) and then complete the CDC, NINSS, Cruse and ASEPSIS tools, or complete these tools for each patient “at the bedside”? The patient postal and telephone questionnaires are not described and readers will be unclear whether patients were merely asked to answer the questions implicit in the 4 instruments or asked to provide a common data set from which the interviewer completed the instruments. There is an absence of research regarding how well patients can self-assess surgical wounds after discharge, even when facilitated through questionnaire or telephone interview, so readers need to be clear about how the data were collected, and be confident that they are likely to be valid. Nevertheless the paper underlines the need for more research in this important aspect of public health and we expect that the authors’ clarification in these aspects will greatly enhance the utility of the paper. Competing interests: None declared