Coding algorithms for identifying patients with cirrhosis and hepatitis B or C virus using administrative data

Pharmacoepidemiol Drug Saf. 2015 Jan;24(1):107-11. doi: 10.1002/pds.3721. Epub 2014 Oct 21.


Background and aims: Despite the use of administrative data to perform epidemiological and cost-effectiveness research on patients with hepatitis B or C virus (HBV, HCV), there are no data outside of the Veterans Health Administration validating whether International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) codes can accurately identify cirrhotic patients with HBV or HCV. The validation of such algorithms is necessary for future epidemiological studies.

Methods: We evaluated the positive predictive value (PPV) of ICD-9-CM codes for identifying chronic HBV or HCV among cirrhotic patients within the University of Pennsylvania Health System, a large network that includes a tertiary care referral center, a community-based hospital, and multiple outpatient practices across southeastern Pennsylvania and southern New Jersey. We reviewed a random sample of 200 cirrhotic patients with ICD-9-CM codes for HCV and 150 cirrhotic patients with ICD-9-CM codes for HBV.

Results: The PPV of 1 inpatient or 2 outpatient HCV codes was 88.0% (168/191, 95% CI: 82.5-92.2%), while the PPV of 1 inpatient or 2 outpatient HBV codes was 81.3% (113/139, 95% CI: 73.8-87.4%). Several variations of the primary coding algorithm were evaluated to determine if different combinations of inpatient and/or outpatient ICD-9-CM codes could increase the PPV of the coding algorithm.

Conclusions: ICD-9-CM codes can identify chronic HBV or HCV in cirrhotic patients with a high PPV and can be used in future epidemiologic studies to examine disease burden and the proper allocation of resources.

Keywords: administrative data; hepatitis B virus; hepatitis C virus; pharmacoepidemiology; validation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Algorithms*
  • Clinical Coding / standards*
  • Clinical Coding / statistics & numerical data
  • Databases, Factual / standards
  • Databases, Factual / statistics & numerical data
  • Female
  • Health Systems Plans / standards
  • Health Systems Plans / statistics & numerical data
  • Hepatitis B / diagnosis
  • Hepatitis B / epidemiology*
  • Hepatitis C / diagnosis
  • Hepatitis C / epidemiology*
  • Humans
  • International Classification of Diseases / standards*
  • International Classification of Diseases / statistics & numerical data
  • Liver Cirrhosis / diagnosis
  • Liver Cirrhosis / epidemiology*
  • Male
  • Middle Aged
  • Retrospective Studies