The Classification of Hospital Acquired Diagnoses (CHADx) (pronounced ‘Chaddix’) will allow hospitals to use routine hospital diagnosis coding to improve patient safety. The CHADx classification groups over 4,500 ICD- 10-AM codes into a manageable hierarchy of 17 classes and 145 sub-classes to characterise hospital acquired complications, for example: post-procedural complications; adverse drug events; accidental injuries; specific infections; metabolic disorders. The occurrence of a hospital acquired complication is identified using the condition-onset flag.
The Classification of Hospital Acquired Diagnoses was developed by researchers at the Australian Centre for Economic Research on Health at the University of Queensland with funding from the Australian Commission on Safety and Quality in Health Care (the Commission). Development of an algorithm to check administrative data for valid recording of the condition-onset flag was part of the early research. During 2010-2011, the Commission mapped the classification to CD-10-AM Seventh Edition, and reviewed and refined the counting rules associated with allocating diagnoses to a CHADx class. The 17 CHADx categories are shown below. In 2013, the classification was updated by mapping to ICD-10-AM Eighth Edition.
The 17 CHADx categories are shown below.
| 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 |
Publications related to the CHADx classification
Jackson TJ, Nghiem HS, Rowell DS, Jorm C, Wakefield J (2011). Marginal costs of hospital acquired conditions: information for priority setting for patient safety programs and research. Journal of Health Services Research and Policy; 16(3):141–146.
Michel JL, Cheng D, Jackson TJ (2011).Comparing the coding of complications in Queensland and Victorian admitted patient data. Australian Health Review; 35, 245–252.
Hauck KD, Zhao X, Jackson TJ (2011). Adverse event rates as measures of hospital performance. Health Policy doi:10.1016/j.healthpol.2011.06.010.
Rowell DS, Jackson TJ (2010). Additional costs of inpatient malnutrition, Victoria, Australia, 2003–2004. Eur J Health Econ; DOI 10.1007/s10198-010-0245-3.
McNair PD, Jackson TJ, Borovnicar D (2010). Public hospital admissions for treating complications of clinical care: Incidence, costs and funding strategy. Australian and New Zealand Journal of Public Health; 34(3):330-333
Rowell DS, Nghiem HS, Jorm C, Jackson TJ (2010). How different are complications that affect the older adult inpatient? Quality and Safety in Health Care; 19(6):e34
New P, Jackson TJ (2010). The costs and adverse events associated with hospitalization of patients with spinal cord injury in Victoria, Australia. Spine; 35(7):796-802.
McNair PD, Borovnicar D, Jackson TJ (2010). The US Medicare Policy to Not Reimburse Hospital Acquired Conditions – what would the impact be in Victoria? Medical Journal of Australia; 193(1):22-25.
Jackson TJ, Michel JL, Roberts R, Jorm C, Wakefield J (2009). A Classification of Hospital Acquired Diagnoses for use with routine hospital data. Medical Journal of Australia (2009) 191(10):544-548.
Jackson TJ, Michel JL, Roberts R, J Shepheard J, Cheng D, Rust J, Perry C (2009). Development of a Validation Algorithm for ‘Condition Onset’ Flagging. BMC Medical Informatics and Decision-Making, 9(48).
Jackson TJ (2009). One Dollar in Seven: Scoping the Economics of Patient Safety, a literature review prepared for the Canadian Patient Safety Institute. Available at: http://www.patientsafetyinstitute.ca/English/research/commissionedResearch/EconomicsofPatientSafety/Documents/Economics%20of%20Patient%20Safety%20Literature%20Review.pdf
Jackson TJ, Moje C, Shepheard J, McMillan A (2009) Voluntary sentinel event reporting vs routinely-coded diagnoses for identifying problems in hospital care. Australasian Journal of Health Services Management, 4(2):39-46.
Jackson TJ, Moje C, Shepheard J, McMillan A (2009). Monitoring sentinel events using routine inpatient data. Asia Pacific Journal of Health Management 4(2):39-46.
McNair PD, Borovnicar D, Jackson TJ, Gillett S (2009). Prospective payment to encourage system wide quality improvement. Medical Care; 47(3):272-278.
Michel JL, Jackson TJ (2009). Australian hospital data: not just for funding. Health Information Management Journal; 38(1):7-12.
Michel JL, Nghiem HS, Jackson TJ (2009). Using ICD-10-AM codes to characterise hospital-acquired complications. Health Information Management Journal; 38(3):18-25.
TJ Jackson and Niall Johnson (2008). Chapter 10: Information Strategy Windows into Safety and Quality in Health Care Australian Commission on Safety and Quality in Healthcare.
Pirson M, Leclercq P, Jackson TJ, Leclercq M, Garrino M, Sion C (2008). Financial consequences of hospital-acquired bacteraemia in three Belgian hospitals in 2003 and 2004. Journal of Hospital Infection; 68:9-16.
Ehsani J, Duckett SJ, Jackson TJ (2007). The Incidence and Cost of Cardiac Surgery Adverse Events in Australian (Victorian) Hospitals 2003-04. European Journal of Health Economics; 8: 339-346.
Ehsani J, Jackson TJ, Duckett SJ (2006). The incidence and cost of adverse events in Victorian hospitals, 2003-04. Medical Journal of Australia, 184(11):551-555.
Jackson TJ, Duckett SJ, Shepheard J, Baxter K (2006). Measurement of adverse events using ‘incidence flagged’ diagnosis codes. Journal of Health Services Research and Policy; 11(1):21-25.
Moje C, Jackson TJ, McNair P (2006). Adverse events in Victorian admissions for elective surgery. Australian Health Review; 30(3):333-343.
Moje C, Jackson TJ, McNair P (2006). Patterns of complications in elective surgery cases; which procedures are ‘adverse event prone’? Australian Health Review.
Cantsileris G, Jackson TJ, Street A (2006). Patterns of first-coded complications in acute episodes of lung cancer care. Health Information Management; 35(1):27-37.
Jackson TJ, Duckett SJ, Shepheard J, Baxter K (2006). Measurement of adverse events using ‘incidence flagged’ diagnosis codes. Journal of Health Services Research and Policy; 11(1):21-25