Predicting cardiovascular risk in England and Wales: prospective derivation and validation of QRISK2
BMJ 2008; 336 doi: https://doi.org/10.1136/bmj.39609.449676.25 (Published 26 June 2008) Cite this as: BMJ 2008;336:1475
- Julia Hippisley-Cox, professor of clinical epidemiology and general practice1,
- Carol Coupland, senior lecturer in medical statistics1,
- Yana Vinogradova, research fellow in medical statistics1,
- John Robson, senior lecturer in general practice2,
- Rubin Minhas, coronary heart disease lead3,
- Aziz Sheikh, professor of primary care research and development4,
- Peter Brindle, research and development strategy lead5
- 1Division of Primary Care, Tower Building, University Park, Nottingham NG2 7RD
- 2Centre for Health Sciences, Queen Mary’s School of Medicine and Dentistry, London E1 2AT
- 3Medway Primary Care Trust, Unit 2, Gillingham, Kent ME7 0NJ
- 4Division of Community Health Sciences: GP Section, University of Edinburgh, Edinburgh EH8 9DX
- 5Avon Primary Care Research Collaborative, Bristol Primary Care Trust, Bristol BS2 8EE
- Correspondence to: J Hippisley-Cox Julia.hippisley-cox{at}nottingham.ac.uk
- Accepted 28 May 2008
Abstract
Objective To develop and validate version two of the QRISK cardiovascular disease risk algorithm (QRISK2) to provide accurate estimates of cardiovascular risk in patients from different ethnic groups in England and Wales and to compare its performance with the modified version of Framingham score recommended by the National Institute for Health and Clinical Excellence (NICE).
Design Prospective open cohort study with routinely collected data from general practice, 1 January 1993 to 31 March 2008.
Setting 531 practices in England and Wales contributing to the national QRESEARCH database.
Participants 2.3 million patients aged 35-74 (over 16 million person years) with 140 000 cardiovascular events. Overall population (derivation and validation cohorts) comprised 2.22 million people who were white or whose ethnic group was not recorded, 22 013 south Asian, 11 595 black African, 10 402 black Caribbean, and 19 792 from Chinese or other Asian or other ethnic groups.
Main outcome measures First (incident) diagnosis of cardiovascular disease (coronary heart disease, stroke, and transient ischaemic attack) recorded in general practice records or linked Office for National Statistics death certificates. Risk factors included self assigned ethnicity, age, sex, smoking status, systolic blood pressure, ratio of total serum cholesterol:high density lipoprotein cholesterol, body mass index, family history of coronary heart disease in first degree relative under 60 years, Townsend deprivation score, treated hypertension, type 2 diabetes, renal disease, atrial fibrillation, and rheumatoid arthritis.
Results The validation statistics indicated that QRISK2 had improved discrimination and calibration compared with the modified Framingham score. The QRISK2 algorithm explained 43% of the variation in women and 38% in men compared with 39% and 35%, respectively, by the modified Framingham score. Of the 112 156 patients classified as high risk (that is, ≥20% risk over 10 years) by the modified Framingham score, 46 094 (41.1%) would be reclassified at low risk with QRISK2. The 10 year observed risk among these reclassified patients was 16.6% (95% confidence interval 16.1% to 17.0%)—that is, below the 20% treatment threshold. Of the 78 024 patients classified at high risk on QRISK2, 11 962 (15.3%) would be reclassified at low risk by the modified Framingham score. The 10 year observed risk among these patients was 23.3% (22.2% to 24.4%)—that is, above the 20% threshold. In the validation cohort, the annual incidence rate of cardiovascular events among those with a QRISK2 score of ≥20% was 30.6 per 1000 person years (29.8 to 31.5) for women and 32.5 per 1000 person years (31.9 to 33.1) for men. The corresponding figures for the modified Framingham equation were 25.7 per 1000 person years (25.0 to 26.3) for women and 26.4 (26.0 to 26.8) for men). At the 20% threshold, the population identified by QRISK2 was at higher risk of a CV event than the population identified by the Framingham score.
Conclusions Incorporating ethnicity, deprivation, and other clinical conditions into the QRISK2 algorithm for risk of cardiovascular disease improves the accuracy of identification of those at high risk in a nationally representative population. At the 20% threshold, QRISK2 is likely to be a more efficient and equitable tool for treatment decisions for the primary prevention of cardiovascular disease. As the validation was performed in a similar population to the population from which the algorithm was derived, it potentially has a “home advantage.” Further validation in other populations is therefore advised.
Footnotes
We acknowledge the contribution of David Stables (EMIS) and EMIS practices contributing to the QRESEARCH database. In particular we acknowledge his contribution in linking the ONS death certificate data to individual records held within EMIS clinical systems so that it could be extracted on to the QResearch database and used for this project. We thank Aneez Esmail (University of Manchester), Ruthie Birger and Chris Millett (Imperial College London), and Nadeem Qureshi (University of Nottingham) for ethnicity coding.
Contributors: JH-C initiated and designed the study, obtained approvals, prepared the data, undertook the analysis and interpretation, and wrote the first draft paper. CC and YV contributed to the development of the protocol, design, and analysis and interpretation and drafting of the paper. CC also undertook some of the primary analyses with JHC. JR and PB contributed to the conception, design, analysis, interpretation, and drafting of article and approved the final draft. RM and AS contributed to suggestions for analysis, drafting, interpretation, and approved the final draft. JH-C is the guarantor.
Funding: No external funding. The authors were funded as part of their clinical or academic positions and meeting expenses were met by the University of Nottingham.
Competing interests: JR chaired and PB and RM were members of the NICE guideline development group on cardiovascular risk assessment. JHC is codirector of QRESEARCH—a not for profit organisation that is a joint partnership between the University of Nottingham and EMIS. EMIS is the leading commercial supplier of IT systems for 56% of general practices in England and Wales and it is likely to implement QRISK2 into its clinical management system. EMIS is likely to also distribute the software package for those using it for academic research or other organisations interesting in implementing QRISK2 into practice or (www.qresearch.org/Public/qriskInformationforClinicians.aspx). RM is a 2008 Harkness Fellow in healthcare policy and practice and is the chair of the cardiovascular working group of the South Asian Health Foundation (SAHF), which receives unrestricted funding from the Department of Health and BHF and unrestricted grants from the pharmaceutical industry. AS chairs the equality and diversity forum of the National Clinical Assessment Service. AS is PI on NHS Connecting for Health’s evaluation of the implementation of the NHS Care Record Service. QRESEARCH undertakes analyses for the Department of Health and other government organisations.
Ethical approval: Trent multicentre research ethics committee.
Provenance and peer review: Not commissioned; externally peer reviewed.