WIESNZ18 cost weights

Documentation and a cost weight table for the WIESNZ18 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. WIESNZ18 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 WIESNZ18 weights table.

The WIESNZ18 methodology is in the same format as that used in other years.  WIESNZ18 includes the following changes from the WIESNZ17:

  • New co-payment developed for Ventricular Assist Devices (VADs) for adults
  • New co-payment developed for Complex Traumatic Limb cases
  • New co-payment developed for Bilateral Mastectomy or Combined Mastectomy and Reconstruction
  • Revised Abdominal Aortic Aneurysm (AAA) co-payment value from 4.3219 to 4.2336
  • Revised Atrial Septal Defect (ASD) co-payment value from 1.0000 to 1.1135
  • Revised Scoliosis co-payment values from 5.5011 to 5.5546
  • Revised Electrophysiology Studies (EPS) co-payment value from 2.2266 to 1.7266
  • Revised Live Donor Nephrectomy (LDN) co-payment value from 1.4357 to 1.4133
  • Revised Endovascular Treatment of Cerebral Aneurysms and Clot Retrieval for Treatment of Strokes co-payment values for DRGs:
    • B02A from 4.5199 to 6.0430
    • B02B from 3.3551 to 2.2658
    • B02C from 3.9556 to 2.4683
  • Revised Isolated Limb Infusion (ILI) co-payment value from 2.6486 to 2.9784
  • Revised weights for NZ DRGs C03W and J11W
  • High outlier per diem weights for high ALOS DRGs have been set more generously to account for the higher proportions of high outlier events in these DRGs
  • Added facility Anglesea Braemar Hospital (8268) to EPS Co-payment
  • Added Waitemata facility WDHB Slark Hyperbaric Unit (3265) to the casemix eligible facilities list.
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