Australian hospital morbidity data on antibiotic resistance.

Reports of infections with drug-resistant microorganisms are included in the National Hospital Morbidity Database (NHMD) at the Australian Institute of Health and Welfare. This database includes data on diagnoses of patients admitted to Australian hospitals, recorded using codes from the Australian version of the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM), and the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Australian Modification. Reports of infections with drug-resistant microorganisms, recorded as either the patient's principal diagnosis, or as a co-morbidity or complication, increased markedly between 1994-95 (when the first reports were included) and 2000-01. Infections resistant to penicillins were the most commonly recorded. The national introduction of the Australian versions of ICD-9-CM in 1995, and of casemix-based funding and management from the mid-1990s, has possibly led to more accurate medical record documentation and improved coding of these infections and are likely explanations for the observed increase in reporting. The NHMD should be considered as a component of a national surveillance system for antibiotic resistance. Its routine data collection covers almost all hospital separations in Australia and is supported by a comprehensive national data collection infrastructure.