1. CPRD: An introduction to the Clinical Practice Research Datalink in Cambridge
Rupert Payne

2. What is CPRD? Governmental, not-for-profit research service
Funded by NIHR and MHRA
VAMP Research (1987)  GPRD (1993)  CPRD (2012)
Provides anonymous general practice health records for public health research, with linkage to additional non-primary care data
University has annual institutional license to online access of data
Managed through Primary Care Unit
Funded by specific projects with additional support from BRC

3. Primary care data collection
Primary care data collected from Vision GP clinical software
Data are recorded as part of routine clinical practice
Coded data, free text
Practices assessed for quality of data recording
Feedback provided to GPs to improve/standardise recording
Data anonymised at practice, then uploaded to CPRD servers for processing and validation
Anonymised routine GP data since 1987, extracted from the Vision system, more recently EMIS, covering 8% of the UK population. Novel linkages can be done and CPRD has systems for facilitating clinical trials

4. The CPRD population 7% sample of UK population
5 million “active” patients
674 Vision practices
Mean practice list size: CPRD=8400, UK=6600
CPRD population 2014
UK population
Ambition is to get all patients in UK. Currently only Vision practices included. Active=live and registered

5. Overview of primary care data
Patient – demographics, registration
Practice – region, collection information
Consultations – date, duration
Clinical – diagnoses, administrative details
Therapy – electronic prescribing
Immunisation – vaccination details
Referrals – to secondary care
Tests – lab results, other measures
Staff – staff type
Surveys
Biological samples
Embedded trials

6. Linkages to other data
Admitted Patient Care Hospital Episode Statistics (HES)
Outpatient Hospital Episode Statistics (HES)
Death Registration Data (Office for National Statistics, ONS)
Cancer registry data (Public Health England)
Cardiovascular registry data (Myocardial Ischaemia National Audit Project, MINAP)
On-going linkage: e.g. mental health (MHMDS), HES A&E, digital imaging
…plus additional bespoke linkages if required

7. How well are things recorded?
Ambition is to get all patients in UK. Currently only Vision practices included
Herrett, Int J Epidemiol 2015

8. CPRD clients
Academia
Pharmaceutical industry
Government

9. Research that can be done with CPRD
Medication and devices
Drug utilisation, compliance and persistence
Pharmacovigilance
Pharmacoepidemiology
Pharmacoeconomics
Life cycle planning
Licence extension research
Health care interventions
Comparative effectiveness research
Outcomes
Clinical outcomes
Patient Reported Outcomes
Public health research
Epidemiology
Health Services research
Risk management research
Risk-benefit research
Risk score development
Clinical trials
Randomisation at point of care
Phase 3 and 4 trials
CPRD observational data resources and services
Disease and drug registers
Pan European and US data

10. Publications using CPRD
Based on search of PubMed for CPRD and GPRD

11. Cambridge work using CPRD
Work led by Autism Research Centre
Women with polycystic ovarian syndrome, and their children, have a greater prevalence of autism
OR 1.58
( )
OR 1.90
( )
Baron-Cohen, unpublished data

12. Cambridge work using CPRD
MPhil student project
Association between service utilisation and multimorbidity in persons with dementia
Browne, unpublished data

13. Cambridge work using CPRD
Long-term outcomes of survivors of critical care
Novel linkage of CPRD and ICNARC-CMP
Pharmacoeconomics of iron salts utilisation
Supporting novel drug development
Medication use in end of life care patients

14. Challenges of using CPRD
Messy data
Big data
Code lists
diabetes codes

15. Independent Scientific Advisory Committee (ISAC)
“To consider and provide advice to MHRA on … all research projects which propose the use of data obtained from the Clinical Practice Research Datalink”
Advises on medical, statistical, epidemiological and methodological aspects
Ensures no governance concerns
All protocols to use data must be first approved by ISAC
Protocols should adhere to IPSE Good Pharmacoepidemiology Practices
Some studies may also require other committee approval (e.g. HRA Confidentiality Advisory Group, HSCIC Data Access Advisory Group)
International Society for Pharmacoepidemiology (ISPE), HRA=Health Research Authority

16. Core CPRD team James Brimicombe Duncan Edwards Amelia Harshfield
Rupert Payne
Kirsty Rhodes