Clinical Epidemiology (Feb 2015)

Positive predictive values of the International Classification of Diseases, 10th revision diagnoses of Gram-negative septicemia/sepsis and urosepsis for presence of Gram-negative bacteremia

  • Søgaard KK,
  • Thomsen RW,
  • Schønheyder HC,
  • Søgaard M

Journal volume & issue
Vol. 2015, no. default
pp. 195 – 199

Abstract

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Kirstine Kobberøe Søgaard,1 Reimar Wernich Thomsen,1 Henrik Carl Schønheyder,2,3 Mette Søgaard1 1Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark; 2Department of Clinical Microbiology, Aalborg University Hospital, 3Department of Clinical Medicine, Aalborg University, Aalborg, Denmark Background: Health care databases are a valuable resource for infectious disease epidemiology if diagnoses are accurately coded. We examined the ability of diagnostic coding to accurately identify Gram-negative bacteremia. Methods: We randomly selected 100 patients among 1,703 patients recorded in the Danish National Patient Register with a diagnosis of either “septicemia/sepsis due to other Gram-negative organisms” (International Classification of Diseases, 10th revision [ICD-10] code A41.5) or “urosepsis” (ICD-10 code A41.9B) who had been admitted at Aalborg University Hospital, Denmark between 1994 and 2012. We estimated the positive predictive value (PPV) of these diagnoses for presence of Gram-negative bacteremia, using microbiological results from blood cultures as standard reference. Complementary clinical information was obtained from the medical records. Results: Of the 100 patients registered with Gram-negative septicemia/sepsis or urosepsis, 72 had blood culture confirmed Gram-negative bacteremia, four patients had monomicrobial Gram-positive bacteremia, 21 patients had a negative blood culture, and three had no blood culture taken. The overall PPV of a blood culture confirmed Gram-negative bacteremia diagnosis was 72% (95% confidence interval [CI]: 62%–81%); for ICD-10 code A41.5 it was 86% (95% CI: 74%–94%) and for ICD-10 code A41.9B it was 55% (95% CI: 39%–70%). The highest PPV was achieved for diagnoses registered in the most recent calendar period (2009–2012) and for secondary discharge diagnoses. Conclusion: Our findings indicated good agreement between ICD-10 code A41.5 “septicemia/sepsis due to other Gram-negative organisms” and Gram-negative bacteremia, whereas ICD-10 code A41.9B “urosepsis” was not suited for identification of Gram-negative bacteremia. Keywords: validation studies, Danish National Patient Register