Safety and Quality > Our Work > Indicators of Safety and Quality > Classification of Hospital Acquired Diagnoses

The Classification of Hospital Acquired Diagnoses (CHADx) (pronounced ‘Chaddix’) allows hospitals to identify, count and monitor adverse events that occur in hospital to support safety improvement efforts.

The CHADx are generated using existing data that is routinely generated from the patient medical clinical record through the assignment of codes using the International Classification of Diseases (ICD-10-AM). The CHADx classification groups over 4,500 ICD-10-AM codes into a hierarchy of 17 classes and 144 sub-classes of adverse events. The adverse events are identified using these diagnosis codes along with the condition onset flag to indicate that the adverse event occurred in hospital.

While the CHADx remains a useful taxonomy of adverse events, the Commission has since developed the Hospital Acquired Complications (HACS) list to provide a shorter, more manageable list of adverse events that can be used to monitor safety. These HACs were prioritised through a clinician led process based on preventability, patient impact (severity), health service impact and clinical priority. The CHADx can be used in conjunction with the HACs to explore adverse events in additional detail.

The CHADx was developed by researchers at the Australian Centre for Economic Research on Health at the University of Queensland for the Australian Commission on Safety and Quality in Health Care (the Commission). During 2010–2011, the Commission mapped the classification to ICD-10-AM Seventh Edition, and reviewed and refined the counting rules associated with allocating diagnoses to a CHADx class. The Commission undertakes regular reviews of the CHADx to maintain reference code sets.  In the latest review, undertaken in 2017, the classification was updated by mapping to ICD-10-AM Tenth Edition.

The Classification of Hospital Acquired Diagnoses (ICD-10-AM, Tenth edition) (Excel 293KB).

The 17 CHADx categories are:

CHADx 1     Postprocedural complications

CHADx 2     Adverse drug events

CHADx 3     Accidental injuries

CHADx 4     Specific infections

CHADx 5     Cardiovascular complications

CHADX 6     Respiratory complications

CHADx 7     Gastrointestinal complications

CHADx 8     Skin conditions

CHADx 9     Genitourinary complications

CHADx 10    Hospital-acquired psychiatric states

CHADx 11    Early pregnancy complications

CHADx 12    Labour, delivery & postpartum complications

CHADx 13    Perinatal complications

CHADx 14    Haematological disorders

CHADx 15    Metabolic disorders

CHADx 16    Nervous system complications

CHADx 17    Other complications.