Transcript Appraisee Training Day - QResearch

QRISK: a new CVD risk score
development & validation
Julia Hippisley-Cox
Calgary
23 Oct 2007
www.qrisk.org
Acknowledgments
coauthors
Carol Coupland
Yana Vinogradova
John Robson
Margaret May
Peter Brindle
statistician
statistician
GP
statistician
GP
www.qrisk.org
Acknowledgments
• EMIS practices
• David Stables & Andy Whitam (EMIS)
• Dept Health
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Goals of presentation
• Background to CVD risk prediction
• Overview of development of QRISK
(new score)
• Key results & validation
• Web calculator
www.qrisk.org
www.qrisk.org
What is Framingham?
• Framingham small town near Boston
• Half the size of Mansfield
• Recruited a cohort of 5,000 people in
1950
• Followed them for > 50 years
• It has been hugely important
www.qrisk.org
www.qrisk.org
Framingham Highlights
1959 – described the ‘silent MI’
1960 – smoking, high BP & high chol bad
1967 – exercise good
1976 – menopause bad (for the heart!)
1978 – psychological factors can be bad
1988 – high HDL good
1991 – risk prediction equation used ALL
AROUND THE WORLD
www.qrisk.org
Why a new CVD risk score?
– Small cohort 50 years ago from one
American town
– Almost entirely white
– Developed during peak incidence CVD in
US
– Overpredicts CVD risk by up to 50%
– Doesn’t include BMI, family history, blood
pressure Rx, deprivation
– But crucially it under estimates risk in
patients from deprived areas
www.qrisk.org
Policy context
• NICE publication of lipid modification
guidelines July 2007
• Statins recommended if CVD risk > 20%
• Need to population screening tool to
identify high risk patients
• Dept Health considering ‘life check’
• Potential utility of routinely collected data
• Interested in self assessment
• Concern about health inequalities
www.qrisk.org
Inverse equity hypothesis
• This shows that when new interventions are
introduced
– Inequalities initially worsen (uptake quickest in
the healthy and wealthy)
– Eventually there is a ‘catch up’ but only when
the wealthy reach a ‘ceiling’
• Need to be proactive to avoid new policies
exacerbating health inequalities
www.qrisk.org
AIM for QRISK
•
•
•
•
•
New CVD risk score
Calibrated to UK population
Better discrimination
Use routinely collected GP data
Include additional known risk factors
(eg FH, deprivation, BMI, BPRx)
www.qrisk.org
QRISK – general approach
• QRISK is a new approach designed
– to tailor management to the individual
patient
– to identify patients at high risk of disease
– to identify those most likely to benefit or be
harmed by treatment
• Present risks and benefits back to patients at
the point of care in an accessible way
www.qrisk.org
QRESEARCH database
–the largest GP database worldwide
–525 practices, 10 million patients ever
–Good historical data > 12 years
–Numerous validation studies
www.qrisk.org
QRISK study cohort
• Derivation cohort (2/3rds practices) &
validation cohort (1/3rd)
• All patients registered 1995-2007
• Men and women aged 35-74
• UK sample free from CVD & diabetes
• Ethnically & socially diverse
• 66,000 Cardiovascular disease events
• 8.3 million person years
www.qrisk.org
Cardiovascular disease
outcomes
• Computer recorded clinical diagnosis
of
– Coronary heart disease
– TIA or Stroke
• Outcome similar to that in JBS2
• Validation against ONS certified
cause of death 94% ascertainment
www.qrisk.org
QRISK risk factors
Traditional risk factors
– Age, Sex, Smoking status
– Systolic blood pressure
– TSC/HDL ratio
– (LVH – recorded prevalence too low)
New risk factors
– Deprivation (townsend score output area)
– Family history premature CVD 1st degree relative
< 60 years
– Body mass index
– BP treatment
www.qrisk.org
Validation
Comparison against Framingham
Independent one third of the database
– Various statistics
– Predicted vs observed CVD events
– Clinical effect in terms of reclassification
of patients into high/low risk
www.qrisk.org
Validation statistics
(note: higher scores are better)
D statistic*
(women)
QRISK
Framingham
1.52
1.39
R squared* 35.5%
(women)
D statistic* 1.42
(men)
31.7%
R squared* 32.4%
(men)
29.1%
1.31
www.qrisk.org
Degree of over prediction
QRISK
Framingham
Women
2%
18%
Men
0%
47%
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% of women at high risk by quintile of deprivation
0
2
4
6
8
10
using QRISK compared with Framingham
Townsend Q1 Townsend Q2 Townsend Q3 Townsend Q4 Townsend Q5
QRISK
© QRESEARCH 2007 version 14
www.qrisk.org
Framingham
% of the UK population
35-74 years at high risk >20%
% All
patients 3574 years
Estimated
numbers
2005
QRISK
Framingham
8.5%
12.8%
3.2
million
4.7
million
www.qrisk.org
Clinically important issue
is degree of reclassification
If we use QRISK rather than Framingham
– Overall one in 10 reclassified
– QRISK identifies different group of
patients who are at higher risk
– Incorrect classification affects patients
from deprived areas (ie more high risk
patients missed)
www.qrisk.org
Strengths of QRISK
– Better calibrated for UK than Framingham
– Less likely than Framingham to over
predict risk
– Better at identifying patients likely to
clinically benefit from treatment
– Includes deprivation which makes it fairer
– Can be implemented into GP computer
systems
– Can be periodically updated and refined
www.qrisk.org
QRISK: Web calculator
• Designed for patients to use
• Also needs integration into clinical
system
Link
http://www.qrisk.org
Username qrisk
Password beta test
www.qrisk.org