NEW ZEALAND HEALTH INFORMATION SERVICE
National Health Index
National Health Index (NHI) Upgrade Programme
The programme of work known as the NHI Upgrade Programme is now approaching completion. This programme was developed to improve and enhance the NHI and its overall architecture.
NHI Background
The NHI provides a mechanism to uniquely identify healthcare users. It was developed to help protect personally identifying health data, particularly data held on computer systems, and to enable linkage between different information systems whilst still protecting privacy.
Access to the NHI is restricted to users authorised by NZHIS, and is permitted by the Health Information Privacy Code of Practice under the Privacy Act 1993. The use of the NHI ensures that when health information is communicated between healthcare facilities, healthcare providers and health practitioners, easily recognisable identifying details such as name and address can be removed.
The NHI database does not contain any clinical information and is not used outside of the health sector.
Key projects
A number of projects made up the NHI Upgrade Programme, including:
- adding new data elements
- reducing the number of duplicate NHI numbers
- introducing a nationally consistent training programme for users of the NHI
- improving the search capabilities of the NHI
- adding the ability to have different views of the NHI
- improving the linking and unlinking of NHIs
- improving access to the NHI, especially for primary healthcare providers, through NOAH (NHI Online Access for Health)
- improving public awareness
- improving address information, including geo-spatial data
- commissioning a privacy impact assessment of the NHI Upgrade Programme
- auditing users of the NHI
- updating some NHI data elements from PHO Enrolment Registers.
New data elements
Existing data elements:
- name
- address
- ethnicity (up to 3)
- date of birth
- date of death
- sex
- Domicile Code (Area Unit Code).
In recent years a number of initiatives have identified the need to improve the quality of information held within the NHI. To assist with the identification of a healthcare user, additional data elements were added to the NHI. These elements are:
- place of birth
- address history
- ethnicity history
- geo-spatial fields (see under heading Address and Geo-spatial Information).
Without additional information, such as the place of birth or address history, the doctor may not be able to correctly identify the patient in his or her care. When a patient cannot be identified a new NHI is created, often a duplicate, thus decreasing the quality of the information on the NHI. This has emphasised the need for these specific additional identifying data elements to improve identification and therefore the quality of healthcare provided.
This additional patient information will not only assist in reducing duplicate creation, but it will also help identify duplication, provide source data for statistical analysis, and assist with population-based health initiatives.
Business rules for those authorised users of the NHI will be used to access the additional data elements.
NHI duplicate reduction
An intensive 12-month duplicate resolution programme, which began in March 2003, identified and linked many existing duplicates. The programme involved NZHIS personnel using specialised software to trawl the NHI looking for potential duplicate numbers. More than 125,000 duplicate NHI numbers were identified and resolved during this period. The identification of duplicate NHIs is an ongoing task, with a number of developed programmes that run each day to identify further duplicates created. The identified duplicate NHIs are then linked, working through a defined process before final approval of linking occurs. This linking of duplicate NHIs is explained below.
Other tools have been developed as part of the NHI Upgrade Programme to help reduce the number of duplicate NHIs being created. These are expanded upon below and include:
a training package to assist those who have access to the NHI
a new search engine
additional data elements to assist with the identification of a NHI number
different views of the NHI via a data warehouse.
The NZHIS Clinical Analysis Services team send monthly reports to providers who create NHIs. These reports show the number of NHIs created and identify those that have been discovered to be duplicates. The reports will provide information that will enable health and disability support services to reduce the number of duplicate NHIs being created.
NHI training programme
Data quality within the NHI reflects the limited training that has been provided to existing users. A need was identified for a nationally consistent training programme that hospitals and other existing NHI users can incorporate within their own training activities.
Training is aimed at better utilisation of existing NHI functionality. The training package was developed in a modular form to allow flexibility in what is presented with topics including NHI structure and use, security, auditing, data quality and access. The package was created with the assistance of representatives from various areas of the health sector, along with a professional training company who also put together the Ethnicity Data Protocols training package. A pilot of the training was carried out prior to final acceptance, with formal training taking place in November 2004 and covering both District Health Boards (DHBs) and Primary Health Organisations (PHOs).
The approach taken to training was ‘train the trainer’, where training was given to those responsible for training in their allocated DHB or PHO to then train users of the NHI. It is envisaged that ongoing or refresher training will be conducted to continually improve data quality of the NHI.
New search engine
One aspect of improving data quality by reducing duplicate NHIs is the ability to accurately search for an individual. The Ministry of Health purchased a new search engine, SSA-Name3, to replace the old name-comparison software used by the NHI. The search-name tables used by SSA-Name3 have been customised to work better for New Zealand’s naming conventions – for example, transliterated names for Māori and Pacific peoples (John / Hanae). SSA-Name3 also ranks the returned names by using a numbering algorithm against the entered name, hence increasing the likelihood of the requested NHI being in the returned list.
An extensive User Acceptance Testing phase was carried out prior to implementation of the search engine, which meant the search engine was implemented into the APIs in a manner that users of the NHI noticed very little change.
Views of the NHI
The ability to exchange information between parties in healthcare is vital for the improvement of health and disability support outcomes. A new use of the NHI, the ‘Views of the NHI’ project created a data warehouse to help identify particular populations. It is intended this information will be used by authorised NHI data analysts and population health programmes. Use of this facility for health programmes will require consideration by a Privacy Impact Assessment for each proposed use that is undertaken, consultation with the public and the appropriate business rules be established.
‘Views of the NHI’ will increase the quality of the NHI by allowing authorised analysts the ability to search for duplicates and conduct reporting related to NZHIS.
NHI Linking and unlinking
When two NHIs are discovered as being for the same healthcare user, a request is made to NZHIS to link the records. New software has been developed that takes NHI link requests and processes them. Business rules are in place to ensure the validity of linking NHIs by searching other data collections administered by NZHIS. This is carried out via the new software application, but can be overridden by the operator if required. An unlinking facility is also available where previously linked NHIs can be unlinked. Notification of linked NHIs is sent to the health sector as confirmation of their request. Through data quality initiatives within NZHIS they to are able to request NHIs to be linked.
In addition to linking/unlinking NHIs, functionality has been developed to identify records that should not be linked (known as ‘Do Not Link’). An example of records that are identified with a status of ‘Do Not Link’ are twins or those people that seem to be similar with matching data elements, but are not the same healthcare user.
Access to the NHI
The NHI was originally developed for public hospitals. To implement NHI access for other health and disability support services and primary healthcare services, NOAH (NHI Online Access for Health) was developed.
NOAH is a web-based solution allowing access to the NHI from an authorised provider’s computer. NOAH utilises the Application Programme Interface (API) that is used to connect public hospitals to the NHI. NOAH was piloted within NZHIS, where heavy users of the NHI put it to the test. General practitioners, Primary Health Organisations (PHOs) and a number of other medical professionals also assisted with the pilot prior to final implementation. Different levels of access can be granted to users working with NOAH. Initially “read-only” access will be available, with “update” and “create” options also possible.
All that is required is a web browser (such as Internet Explorer or Netscape version 4.0 and up), a digital certificate, and a Health Intranet connection.
Public awareness
One of the key goals of the Upgrade Programme was to improve public awareness of both the purpose and current use of the NHI. To help achieve this goal, the Ministry of Health prepared a brochure and poster to inform the public about the NHI, the information recorded on the NHI and how the Health and Disability Sector currently use the NHI. In deciding the content and format of the brochure and poster the Ministry of Health sought advice from a consumer advisory group. These are now available in patient waiting areas of hospitals and general practitioners as well as Citizens’ Advice Bureaux.
As part of this project other avenues for communication were also used. These included:
- consulting with and working through a Consumer Advisory Group
- public release of the NHI brochure and poster
- articles in NZ Doctor, Health News and the NZHIS website
- updating the NZHIS web site about the NHI and the Upgrade Programme
- providing presentations on the programme’s progress to health sector stakeholders.
A programme of consultation was begun under the ‘Improve NHI for Māori’ project within the NHI Upgrade Programme. It has encouraged Māori providers and collectives to see the NHI as a tool for looking at Māori populations, for extracting Māori data and using data for more effective service planning. The message was also trialled on some Māori Health groups. Of particular interest to Māaori Health groups and the DHB General Managers of Māori Health has been the consideration of the iwi / hapū variable as a new data element. This has not been implemented as yet.
Address and geo-spatial information
The process by which geographic co-ordinates of a location are determined from a street address or other location descriptors is called geo-coding. These co-ordinates can then be used by computer programs to graphically represent geographic locations and their relationship with specific types of data, such as disease patterns in a DHB area. Geo-spatial fields have been added to the NHI to assist with graphically representing address data, including:
- DHB Code
- Territorial Local Authority Code
- meshblock
- latitude and longitude (X/Y co-ordinates).
In September 2004, Health Information Strategy and Policy (HISP) established the work programme “Address Validation and Geo-coding Strategy for the Health and Disability Sector” (the strategy). The purpose of this work programme was to report on current operational issues with geo-coding address data and to produce a strategy for future improvements.
The major output from the strategy will provide sector-approved standards for data structures and processes. In addition to address validation and geo-coding standards, the strategy will provide the guidance and coordination to help the sector maintain address data in a consistent manner and help introduce efficiencies.
Future improvements to the NHI will use address validation and geo-coding standards to implement processes that maintain address and location data, using fields added as part of the current NHI Upgrade Programme.
The new NHI fields comply with the base standards that will be adopted by Health Information Standards Organisation (HISO) as part of developing the geo-coding standards.
Privacy Impact Assessment
A paper was commissioned to discuss and assess the privacy implications of the upgrade of the NHI. The object was to identify any issues and present them to decision makers who were then able to make decisions as to whether and how any risks could be mitigated, or whether in a particular case a privacy risk or impact was outweighed by a clinical benefit to the individual concerned, or by some public policy benefit such as improved accuracy of funding allocations, better resources for epidemiological research, or better planning for longer-term health policy.
NHI audit
The National Health Index (NHI) is a key part of health and disability support services. To be fully effective the NHI must be secure, and be supported by robust policies and procedures that protect privacy.
Because anyone can become ill or injured at any time, the NHI must be available at all times so authorised users can access information. Auditing is the most useful means of ensuring that authorised users do not abuse the trust that has been placed with them. The audit project was implemented as a pro-active and ongoing process to audit all of the users of the NHI and verify that the NHI is only accessed for legitimate reasons.
Updating NHI data elements
To assist with improvements in the NHI data quality, the address and ethnicity data held on PHO enrolment registers is updated onto the NHI where there is a match in the NHI between the two data collections. In the past address and ethnicity details were predominantly updated by hospitals. PHO enrolment registers have now given NZHIS the opportunity to update the NHI with more recentinformation. Information is updated from the registers every three months once registers have been received by the PHOs.