Ethnicity and prediction of cardiovascular disease: performance of QRISK2 and Framingham scores in a U.K. tri-ethnic prospective cohort study (SABRE--Southall And Brent REvisited)

Abstract

Objective: To evaluate QRISK2 and Framingham cardiovascular disease (CVD) risk scores in a tri-ethnic U.K. population.

Design: Cohort study.

Setting: West London.

Participants: Randomly selected from primary care lists. Follow-up data were available for 87% of traced participants, comprising 1866 white Europeans, 1377 South Asians, and 578 African Caribbeans, aged 40-69 years at baseline (1998-1991).

Main outcome measures: First CVD events: myocardial infarction, coronary revascularisation, angina, transient ischaemic attack or stroke reported by participant, primary care or hospital records or death certificate.

Results: During follow-up, 387 CVD events occurred in men (14%) and 78 in women (8%). Both scores underestimated risk in European and South Asian women (ratio of predicted to observed risk: European women: QRISK2: 0.73, Framingham: 0.73; South Asian women: QRISK2: 0.52, Framingham: 0.43). In African Caribbeans, Framingham over-predicted in men and women and QRISK2 over-predicted in women. Framingham classified 28% of participants as high risk, predicting 54% of all such events. QRISK2 classified 19% as high risk, predicting 42% of all such events. Both scores performed poorly in identifying high risk African Caribbeans; QRISK2 and Framingham identified as high risk only 10% and 24% of those who experienced events.

Conclusions: Neither score performed consistently well in all ethnic groups. Further validation of QRISK2 in other multi-ethnic datasets, and better methods for identifying high risk African Caribbeans and South Asian women, are required.

Figure 1

Observed and predicted risk over 10 years of follow-up.

Figure 2

Plots of 10 year observed risk versus predicted risk of cardiovascular disease (CVD) (by tenths of predicted risk) for QRISK2 and Framingham (with South Asian male ethnicity adjustment) risk scores: (i) Men; (ii) Women.