WIESNZ15 cost weights

Documentation and a cost weight table for the WIESNZ15 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. WIESNZ15 uses AR-DRG 6.0x which is based on ICD-10-AM/ACHI 6th Edition codes. A new set of cost weights are provided in the WIESNZ15 weights table.

ICD-10-AM/ACHI 8th Edition was implemented for all event records that had an event end date on or after 1 July 2014.  Event records coded in 8th Edition have their codes back-mapped to ICD-10-AM/ACHI 6th Edition.

WIESNZ15 includes the following changes from the previous year:

  • A new DRG mapping so that pelvic exenteration surgery event records group to NZ DRG N01Z Pelvic Evisceration and Radical Vulvectomy
  • A new co-payment for treatment of cerebral aneurysms (CA) via endovascular repair
  • Extended the scoliosis eligibility rule to cover the DHB funding agency rather than the facility
  • 77 new same day (SD) or one day (OD) designations have been introduced to better direct revenue to admitted patient event records rather than ED or similar short stay events
  • Co-payment values have been adjusted for AAA, ASD and scoliosis. No adjustments were made to the EPS co-payment as further analysis was deemed necessary.LDN and MV were not reviewed
  • New purchase unit code created for Metabolic Services M24001 Metabolic services – inpatient services (DRGs)
  • Revision of the payment for tonsils and adenoid (T&A) procedures with a sleep apnoea diagnosis to be funded at a similar level to T&A cases without a sleep apnoea diagnosis.This was achieved by giving the DRG E02C Other Respiratory System OR Procedures W/O CC a SD designation
  • Ophthalmology injections and excision skin lesion cost weights have been revised
  • Facility ‘Mater Misericordiae Health Services’ (9136) added to the casemix eligible facilities list
  • Primary maternity tables for initial filters, flags, RVUs and flow diagram revised
  • Same day blood transfusion PU allocation revised
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