An explanation of hospital surgical activity data

• Each DHB has a service agreement for a certain volume of activity with each of its surgical services. The volume of activity is measured in case weights. Case weights measure the relative complexity of the treatment given to the patient. This volume of activity is made up of both acute and elective cases. An acute case is one that has to be treated immediately.
• The scope of activity included within a specific service agreement can vary between DHBs. For example, some DHBs have a separate service agreement for paediatric surgery; others include paediatric surgery within their general surgery service agreement.
• From time to time, some procedures may be shifted from one service to another. This will result in changes — some quite large — to the amount of activity reported in those services. However, the overall amount of work undertaken remains the same.
• For the following reasons, the total numbers discharged from any given surgical service will not equal the total number of operations performed by that surgical service:
• Discharges from surgical services simply indicate that a patient passed through a surgical service and was discharged from that service. They do not have to receive an operation to be included in this dataset.
• If a patient undergoes more than one operation they are still only recorded as a single discharge.
• A number of patients receiving an operation will, after that operation, be transferred to a medical specialty, such as respiratory medicine, to receive further treatment before discharge. Such patients will then be counted as a medical discharge, even though as part of their course of treatment they received an operation.
• The Patient Discharge data (Tables 1 and 2) includes only those patients coded to surgical specialties — no medical specialties are included. However, the Standardised Discharge information (Table 3) includes Angioplasty, which is reported against Cardiology (a medical specialty). Therefore, the Standardised Discharge dataset is not limited to procedures delivered in surgical services. It includes all the procedures delivered regardless of which service they were delivered in.
• Further technical information on the specific inclusions and exclusions in the data is available on request, e-mail data-enquiries@health.govt.nz.

1. Procedures done on an outpatient basis, such as removal of melanoma, or those purchased as specific items, such as some minor eye operations.
2. Investigative procedures, such as endoscopy or cardiac catheters.
3. Emergency Department activity.

For each DHB, five tables of information are available – three that tell you about the services received by people living in your DHB area (‘DHB of Domicile’), and two that tell you about the services delivered by hospitals in your DHB area (‘DHB of Service’).

Tables 1–3 (What services did people living in your DHB area receive?) provide a picture of the number of patients treated who reside in that DHB region, irrespective of where they received their treatment. This answers the question ‘Over time, is that DHB’s population receiving more or less service?’

Tables 4 and 5 (What services did your DHB provide?) give a picture of the volume of work delivered by that DHB’s providers irrespective of where the patients come from. This answers the question ‘Over time, is that DHB delivering more or less service for its own residents and, where relevant, those of other DHBs?’

Presenting the information in these different ways illustrates the fact that while secondary hospitals have a more limited range of services than do tertiary hospitals, residents of all DHBs access a full range of services.