WIESNZ17 cost weights

Documentation and a cost weight table for the WIESNZ17 methodology.


The New Zealand Casemix Framework for Publicly Funded Hospitals provides the definitions for inclusion of hospital events in casemix funding together with information related to the calculation of cost weights for these events and the assignment of events to purchase units. WIESNZ17 uses AR-DRG 7.0 that is based on ICD-10-AM/ACHI 8th Edition codes. ICD-10-AM/ACHI 8th Edition was implemented for all event records that had an event end date on or after 1 July 2014.  A new set of cost weights are provided in the WIESNZ17 weights table.

The WIESNZ17 methodology is in the same format as that used in other years.  WIESNZ17 includes the following changes from the WIESNZ16:

  • ICD-10-AM/ACHI diagnosis and procedure codes including descriptors have been updated to 8th Edition
  • DRGs and descriptors have been updated to AR-DRG v7.0
  • Radiotherapy mapping for medical DRGs has been maintained however events map to a new NZ specific DRG R64W Radiotherapy
  • DRGs excluded from mechanical ventilation days have been updated
  • NZ specific DRG A39W has been revised to include only pelvic exenteration events, with an expanded definition to include male events
  • ASD co-payment value revised from 1.5493 to 1.0000
  • Scoliosis co-payment rule revised to include paediatric events provided at Counties Manukau and Waikato DHBs. Co-payment value revised from 5.7751 to 5.5011
  • EPS co-payment rule revised to include the procedure code 38518-00 [609] Ventricular muscle ablation to allow for transcatheter ventricular ablation
  • The live donor nephrectomy co-payment now only applies to DRG L04B Kidney, ureter and major bladder  procedures for non-neoplasm W/O catastrophic CC with the co-payment value being revised from 0.7049 to 1.4357
  • Endovascular treatment for cerebral aneurysm co-payment rule has been revised to include clot retrieval procedures for strokes with the co-payment value revised from 5.9718 to 4.5199
  • A new co-payment has been developed for the isolated limb infusions procedure (ILI)
  • Due to the new structure of the neonatal major diagnostic category in AR-DRG v7.0 well newborn and neonate definitions have been revised
  • Scope exclusion rules for cystoscopy, bronchoscopy, ERCP, colonoscopy, and gastroscopy have been revised which has led to a small number of newly excluded events.
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