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 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.