Individual Referencing
Systems
Anthea Springbett
Programme Principal SHIS-R
NHS Information Services Division
Structure of workshop
•
Introduction
•
Referencing and linkage
•
ISD linkage
•
CHI
•
Practical application of CHI
•
Population spine
What is individual referencing?
•
Administrative systems
–
organising information
–
retrieving information
•
Audit
•
Linking information
–
over time
–
across space
A&E Maternity
BIRTH
DEATH
Scottish Birth Record SBR
Child health surveillance Immunisation
GP consultations
Dental SMR13
Out patients SMR00 Hospital Admissions SMR01
Mental Health SMR04
Prescribing Screening
Cancer registrations SMR06
Cancer registry
ISD: collecting data from cradle to grave …
From conception
through
childhood...
• Mothers ante-natal records • Abortion Notifications
• Maternity – CHI Number • Neonatal record
• Register birth - NHS number • Register with GP • Child-health surveillance • Immunisation • GP Appointments • Dental Appointments • Outpatients
…adulthood until death
• Outpatients
• A&E attendance
• General hospital admission • Prescribing
• Well woman/man screening • Cancer registration
• Cancer treatment
• Audit of clinical treatment
• Stroke - hospitalisation & rehab • Community care
Why is referencing so useful for linkage?
•
Data collection systems
–
point of delivery
–
episodic
–
many sources
–
different protocols
What is the alternative?
•
Personal information
–
name
–
address
–
date of birth
•
Contextual information
–
date/time of admission
What are the advantages of referencing?
•
Simplicity
•
Privacy
•
Consistency
•
Flexibility
•
Efficiency
… and what are the disadvantages?
•
Completeness
•
Accuracy
•
Maintenance
A&E Maternity
BIRTH
DEATH
Scottish Birth Record SBR
Child health surveillance Immunisation
GP consultations
Dental SMR13
Out patients SMR00 Hospital Admissions SMR01
Mental Health SMR04
Prescribing Screening
Cancer registrations SMR06
Cancer registry
ISD: collecting data from cradle to grave …
CHI (Community Health Index)
•
Scottish
•
Introduced first in Tayside
•
Assigned at birth
•
Coverage – all NHS patients
•
Maintenance – PSD
Record linkage in ISD
• History
• 1960s: routine recording of patient identifiers • 1970s: linkage programs
• 1980s: permanently linked datasets • 1990s: CHI
• Probability Matching
• Quantifies the quality of a potential match • Enables routine linkage of datasets
• Use of CHI in linkage
• Unique patient identifier for each patient • Protects patients’ privacy
Linking records
(Donald Duck and Daisy Swan)
Surname Soundex Forename Date of birth Post code CHI number
Duck D200 Donald 1 January 1955 DL1 2BY 0101551234 Dukk D200 Donald 1 January 1955 DL2 3SL 0101551234
Surname Soundex Forename Date of birth Post code CHI number
Swan S500 Daisy 24 December 1959 AZ1 2BY 2412591234 Duck D200 Daisy 24 December 1959 DL2 3SL 2412591234
Population spine
•
Master index
•
Independent systems
•
Read-through across systems
•
Data obtained from several systems
Example of recent ISD linkage
• T4 HEAT target to reduce emergency admissions • Linkage of NHS24, SAS, ACaDMe, ‘Out of Hours’
and A&E admissions
• National linkage to replace local data • Follow patient pathways
The future (1) - SHIP
• Scottish Health Informatics Programme
– Funded by Wellcome Trust, MRC, ESRC – Academic/NHS consortium
– 2009/10 to 2012/13 • SHIP is:
– “an ambitious, Scotland-wide research platform for the collation, management, dissemination and analysis of Electronic Patient Records (EPRs)”
ISD’s contribution to SHIP (SHIS-R)
• Procedures for secure access
• Linkage agent and safe haven
• National routine NHS Scotland datasets available to researchers throughout UK
• Portal for knowledge about availability of appropriate health related data
• Archiving
• Metadata
Indexing service sends key to Linkage Agent within Safe Haven
Datasource 1 Datasource 2 Project code Study numbers Payload data Project code Study numbers Payload data Indexing Service Datasource 1 Local IDs Names Addresses Dates of birth Datasource 2 Local IDs Names Addresses
Dates of birth Project code
Local IDs
Study numbers
Project code Local IDs
Study numbers
Linkage Agent within Safe Haven Project code
Study numbers
Payload data Payload data
Indexing service
• The indexing service uses CHI as a population reference file • Use of a population reference file maximises leverage of
linkage
• The indexing service does not release CHI numbers or CHI
data but only index numbers
• Different sets of index numbers are used for each data set to be linked
The role of the research coordinator
Data permissions Data release
Non-NHS Data controller National PAC (ISD, GROS) Local PAC or equivalent (NHS HB) Non-NHS dataset Local HB dataset ISD dataset Referral of data request Data request Research Coordinator Advice & guidance Training Researcher approval Safe haven Researcher approval and secure access
Linker (NSS) National Indexing Service Creation and storage of linked dataset
The future (2) - NDLC
•
National Data Linkage Centre
•
ISD and NRS
•
Cross-sectoral data linkage
•
Utilising existing expertise
•
Population spine