Ethnicity and Prediction of Cardiovascular Disease
Total Page:16
File Type:pdf, Size:1020Kb
Heart Online First, published on November 1, 2013 as 10.1136/heartjnl-2013-304474 Epidemiology Heart: first published as 10.1136/heartjnl-2013-304474 on 1 November 2013. Downloaded from ORIGINAL ARTICLE Ethnicity and prediction of cardiovascular disease: performance of QRISK2 and Framingham scores in a UK tri-ethnic prospective cohort study (SABRE—Southall And Brent REvisited) Therese Tillin,1 Alun D Hughes,1 Peter Whincup,2 Jamil Mayet,3 Naveed Sattar,4 Paul M McKeigue,5 Nish Chaturvedi,6 On behalf of the SABRE Study Group ▸ Additional material is ABSTRACT white US community) predicted no difference in published online only. To view Objective To evaluate QRISK2 and Framingham risk between South Asians and white Europeans please visit the journal online cardiovascular disease (CVD) risk scores in a tri-ethnic either with diabetes or in the general population in (http://dx.doi.org/10.1136/ 12 heartjnl-2013-304474). UK population. terms of CVD mortality and CHD and stroke Design Cohort study. risk.13 14 The Framingham score has been criticised 1International Centre for Circulatory Health, National Setting West London. for lack of socioeconomic adjustment, overestimat- Heart and Lung Institute, Participants Randomly selected from primary care ing risk in low risk and affluent populations, while Imperial College London, lists. Follow-up data were available for 87% of traced underestimating risk in less affluent – London, UK participants, comprising 1866 white Europeans, populations.15 17 2Division of Population Health Sciences and Education, St 1377 South Asians, and 578 African Caribbeans, aged More recently, QRISK2, including adjustment George’s University of London, 40–69 years at baseline (1998–1991). for deprivation and ethnicity, has undergone London, UK Main outcome measures First CVD events: internal and external validation using UK primary 3 National Heart and Lung myocardial infarction, coronary revascularisation, angina, care datasets.418However, the performance of Institute, Imperial College transient ischaemic attack or stroke reported by QRISK2 in ethnic minorities was not reported sep- London, London, UK 18 4Institute of Cardiovascular and participant, primary care or hospital records or death arately. Earlier guidelines from the UK National Medical Sciences, University of certificate. Institute for Health and Care Excellence (NICE) Glasgow School of Medicine, Results During follow-up, 387 CVD events occurred in recommended lower risk thresholds for South Glasgow, UK 5 men (14%) and 78 in women (8%). Both scores Asian men (but not women), by multiplying the Centre for Population Health 319 Sciences, University of underestimated risk in European and South Asian Framingham risk scores by 1.4, although this Edinburgh, Edinburgh, UK women (ratio of predicted to observed risk: European approach remains untested. In 2010 NICE recom- http://heart.bmj.com/ 6International Centre for women: QRISK2: 0.73, Framingham: 0.73; South Asian mended that the Framingham risk equation would Circulatory Health, National women: QRISK2: 0.52, Framingham: 0.43). In African no longer be recommended for CVD risk assess- Heart and Lung Institute, Caribbeans, Framingham over-predicted in men and ment, but that it could be considered together with Imperial College London, London, UK women and QRISK2 over-predicted in women. other risk scores such as QRISK2. We evaluated the Framingham classified 28% of participants as high risk, performance of Framingham319) and QRISK2 Correspondence to predicting 54% of all such events. QRISK2 classified scores as predictors of CVD outcomes over Therese Tillin, International 19% as high risk, predicting 42% of all such events. 10 years of follow-up in European, South Asian, Centre for Circulatory Health, on September 30, 2021 by guest. Protected copyright. National Heart and Lung Both scores performed poorly in identifying high risk and African Caribbean men and women in a UK Institute, Imperial College African Caribbeans; QRISK2 and Framingham identified population based cohort. London, 59-61 North Wharf as high risk only 10% and 24% of those who Road, London W2 1LA, UK; experienced events. METHODS [email protected] Conclusions Neither score performed consistently well SABRE (Southall And Brent REvisited) is a Received 17 June 2013 in all ethnic groups. Further validation of QRISK2 in tri-ethnic, community based cohort from Southall Revised 3 September 2013 other multi-ethnic datasets, and better methods for and Brent (London).20 Participants aged 40–69 Accepted 2 October 2013 identifying high risk African Caribbeans and South Asian years at baseline (1988–1991) were randomly women, are required. selected from primary care physician lists (n=4063) and workplaces (n=795). Ethnicity was agreed with the interviewer based on self-report, parental INTRODUCTION origins, and appearance. All South Asians and Risk prediction is a cornerstone of strategies African Caribbeans were migrants. South Asians for prevention of cardiovascular disease (CVD).12 originated from the Indian subcontinent (India The last 30 years have seen the derivation and 90.3%, Pakistan 9.4%). Most African Caribbeans – modification of numerous risk calculators.3 10 (92.5%) originated from the Caribbean and the People of South Asian origin experience greater remainder from West Africa. To cite: Tillin T, Hughes AD, risk than people of European origins, while in the At baseline, participants underwent fasting and Whincup P, et al. Heart Published Online First: UK, people of African Caribbean origin have lower post-glucose challenge blood tests, blood pressure [please include Day Month risks of coronary heart disease (CHD), but higher measurements, ECG, anthropometry, and com- Year] doi:10.1136/heartjnl- risks of stroke.11 Earlier UK studies reported that pleted a health and lifestyle questionnaire.20 2013-304474 the Framingham score (developed in a largely Minnesota criteria21 identified major Q waves on CopyrightTillin T, et al .ArticleHeart 2013; author0:1–8. doi:10.1136/heartjnl-2013-304474 (or their employer) 2013. Produced by BMJ Publishing Group Ltd (& BCS) under licence.1 Epidemiology Heart: first published as 10.1136/heartjnl-2013-304474 on 1 November 2013. Downloaded from ECG. Atrial fibrillation and left ventricular hypertrophy (LVH) majority of participants (see online supplemental table S1). We were identified in a subset of ECGs from European and African examined ethnicity specific calibration of each score by plotting Caribbean participants.20 Diabetes was determined using WHO observed against predicted risk by tenths of predicted risk and criteria22 or doctor diagnosed diabetes. Seated resting blood by calculation of the Brier score (lower values indicate greater pressure was taken as the average of two readings measured accuracy) and the ratio of predicted to observed risk. using a random zero sphygmomanometer (Hawksley, UK). We assessed discrimination (differentiation of scores between Deaths were reported by the Office for National Statistics. participants who did and did not experience an event) by calcu- During 2008–2011, survivors were invited to join a follow-up. lating the area under the receiver operating characteristics curve This included a health and lifestyle questionnaire and/or (AUROC) statistic for the end point of combined fatal and non- primary care medical record review and/or attendance at our fatal CVD events. In addition, we calculated the D statistic (a clinic at St Mary’s Hospital, London. Hospital episode statistics measure of separation based on the ability of the prognostic (HES) were obtained. index to discriminate between participants’ risks of an event) At follow-up we obtained data on family history of CHD, and R2 statistic,23 24 which estimates the proportion of defined as angina or heart attack diagnosed in a parent aged explained variance (higher values indicate better under 60 years. We assigned Townsend 2001 deprivation scores discrimination). based on output areas.4 We compared high (≥20%) and low risk groups for each risk score and examined proportions of participants who would be Identification of cardiovascular events during the first reclassified to a different category using the alternative risk 10 years of follow-up score and the proportion of observed events identified by high We mirrored end points for QRISK2 (first myocardial infarc- risk classification. tion, angina, CHD, stroke, transient ischaemic attack). We Sensitivity analyses—We repeated the above analyses recalcu- included coronary revascularisation procedures as these proce- lating QRISK2 and Framingham scores19 (a) using parental dures incur a diagnosis of CHD on the general practice history data, (b) using the stricter definition of CHD, and (c) database. using the subset of African Caribbeans and Europeans with For CHD, we identified the first event from any of the follow- baseline ECG data for definition of LVH. ing sources: All analyses were conducted in STATAV.12. A. Cause of death includes International Classification of Disease (ICD) 9 codes 410-415 or ICD10 codes I200-I259. B. Primary care record review. RESULTS C. Participant reported coronary revascularisation or acute Of the original 4539 participants without CVD at baseline, myocardial infarction. 4228 were traceable at follow-up. Follow-up data were available D. HES: diagnostic ICD9 codes 410-415 or ICD10: I200-I259 for 3821 (90%). Of measured risk factors, 89 (2.3%) partici- or the Office of Populations and Surveys ‘Classification of pants had missing values for lipids, a Townsend