06 July 2007
Br Med J 2007; Advance online publication
The cardiovascular disease risk score QRISK identifies people at risk more accurately than the Framingham model or the Scottish score ASSIGN, say UK researchers.
"QRISK includes additional variables that allow better tailoring of management to the individual patient and will help minimize health inequalities," the authors write in an advance online publication by the British Medical Journal.
Julia Hippisley-Cox (University of Nottingham) and colleagues derived a new cardiovascular risk score, the QRISK, and validated its performance against the Framingham algorithm and the ASSIGN score.
The derivation cohort consisted of 1.28 million patients, aged 35-74 years, who were free of diabetes and cardiovascular disease, and registered at 318 practices between 1995 and 2007. The validation cohort consisted of 0.61 million patients from 160 practices.
The Framingham algorithm over-predicted cardiovascular disease risk at 10 years by 35%, ASSIGN by 36%, and QRISK by 0.4%.
QRISK predicted 8.5% of patients aged 35-74 years to be at high risk compared with predictions of 12.8% for the Framingham algorithm and 14.0% for ASSIGN.
Using QRISK, 34.5% of women and 72.9% of men aged 64-75 years were considered at high risk compared with 24.1% and 86.0%, respectively, using the Framingham model.
"Measures of discrimination tended to be higher for QRISK than for the Framingham algorithm and it was better calibrated to the UK population than either the Framingham or ASSIGN models," the team comments.
UK estimates based on QRISK give 3.2 million patients as being at high risk, 4.7 million based on the Framingham algorithm, and 5.1 million with ASSIGN.
Overall, 9% of the patients would be reclassified as being high-to-low risk or vice versa using QRISK, compared with the Framingham algorithm.
Hippisley-Cox et al conclude: "We think that QRISK is likely to provide more appropriate estimates of cardiovascular disease risk in contemporary UK populations and better discriminate those at high risk on the basis of their age, sex, and social deprivation as well as existing antihypertensive treatment.
"It is likely therefore to be a more equitable tool to inform patient management decisions."
Luc Bonneux (Netherlands Interdisciplinary Demographic Institute, The Hague) commented in a related editorial: "There is little medical of scientific justification that risk calculations with arbitrary thresholds should supersede informed choice. Absolute risk scores do not offer an easy escape from moral choices."