WAITING LIST PRIORITY SCORING SYSTEMS: IS THE NEW ZEALAND SYSTEM VALID?

Abstract

The New Zealand health score was developed by the New Zealand government to ensure that patients with the greatest needs were given priority. It allows explicit rationing of health care by clinical priority rather than waiting time (the current UK system). The scoring system has not been validated against an accepted measure of health status and the aim of this study was to compare the New Zealand score with the SF-36.

Patients on the orthopaedic waiting list for hip or knee replacement were sent postal questionnaires to collect demographic data and complete an SF-36 and New Zealand score.

581 patients were sent questionnaires. The response rate was 72% and data was available on 243 knee replacement and 168 hip replacement patients. For patients awaiting hip replacement there was good correlation between the NZ and all health domains of the SF-36 (correlation coefficient: 0.19 – 0.62). In contrast, there was poor correlation between the NZ score and the SF-36 for patients awaiting knee replacement with only physical function having a significant correlation (coefficient 0.25). Breakdown of the NZ score into pain and function components did not improve the correlation with SF-36 scores for these patients.

The New Zealand clinical priority scoring system correlates well with health status, as measured by the SF-36, for patients with hip arthritis awaiting hip replacement. However, the NZ score does not correlate with the SF-36 for patients awaiting knee replacement. This system is now being used by some centres in the UK for waiting list management but has been introduced without comparison to any well-established measures of health status. Its use for the prioritisation of patients who require knee replacement should be questioned.