Multivariate risk estimation for coronary heart disease: the Busselton Health Study

Abstract

ortality from coronary heart disease (CHD) inAustralia has been M falling for more than 20 years, but the rates remain high and a cause for concern. Risk factors associated with increased morbidity and mortality from CHD include hypertension, smoking, elevated serum total cholesterol, low high-densitylipoprotein (HDL) cholesterol, diabetes, obesity, left ventricular hypertrophy and previous history of CHD. Moderate levels of alcohol consu.mption are associated with decreased morbidity and mortality from CHD.CHD is a multifactorial disease and risk should be estimated by assessing all cardiovascular risk factors simultaneously. A simple method for obtaining an integrated or composite risk score is to categorise an individual as being 'at risk' or 'not at risk' according to whether the risk factor exceeds some arbitrary threshold, and then to add up the number of factors with 'at risk' values. This method is easily applied in practice and will identify high-risk subjects.However, CHD occurs in individuals with moderate elevations of several risk factors as well as in individuals who have extreme elevations of few risk factors, and therefore this simple composite score may fail to identify high-risk subjects with multiple risk factors at moderately elevated values which do not exceed the thresholds.A more effici'ent approach is to use a continuous multivariate risk score which does not use thresholds and will recognise that an individual with borderline elevation of two or three risk factors may be at the same risk as another individual with a serious elevation of one of them. ' Investigators from the Framingham Heart Study in the United States have developed risk scores for predicting the development of CHD4.5 and handbooks and programs for calculators have been de~eloped.~.' The best known of these scoring systems calculates risk based on age, sex, systolic or diastolic blood pressure, plasma total cholesterol, ECG evidence of left ventricular hypertrophy, diabetes and smokmg status. More recently published equations have also included HDL cholesterol.* A number of other studies have produced risk scoring systems for men.'-'* There are few risk scores developed for women. No CHD risk scores have been developed from Australian data.The development of several risk scores has been partly motivated by the belief that risk scores developed from one population may not be applicable to another population. A review of 15 published estimated logistic risk functions for CHD morbidity/mortality found that there were differences in the odds ratios between studies and the authors concluded that the 'use of a scoring system derived from logistic regression to produce a measure of risk for a different population may be more misleading than advantageous'.13 However, some evaluations of risk scores derived from one population and applied in other settings produced findings that do not support this vie^.'^'^-'^ Nevertheless, locally derived scores would be more acceptable to clinicians and general practitioners and thus more lik...

Folate and vitamin B-12 and risk of fatal cardiovascular disease: cohort study from Busselton, Western Australia

“…18 19 As the age adjusted and multivariate adjusted results were similar, only the multivariate results are reported. We did separate analyses for men and women and for the whole cohort and the subcohort who had no cardiovascular disease at baseline.…”

“…We also included other baseline risk factors for cardiovascular disease in the multivariate analysis: age, systolic and diastolic blood pressure, body mass index, serum cholesterol concentration, white cell count, smoking, menopause (in women), treatment for diabetes, treatment for hypertension, alcohol intake, and history of coronary heart disease, stroke, or leg claudication. 18 19…”

A risk score predicted coronary heart disease and stroke in a Chinese cohort

“…Since the Framingham CHD risk score was developed [3], many other risk scores have subsequently been published for local populations [13,19]. It is clear that risk prediction scores from Caucasian cohorts can not necessarily be applied to predict risk in non-Caucasians and other ethnic/race groups [6].…”

Cost–effectiveness analysis of genetic screening for the Taq1B polymorphism in the secondary prevention of coronary heart disease

“…The RR of first-ever stroke in those with CHD and the RR of first-ever CHD in stroke subjects were derived from the Danish MONItoring of trends and determinants in CArdiovascular disease study (MONICA) [22][23][24]. The RR of stroke and CHD in those treated with ezetimibe was derived from an unpublished meta-analysis, which included seven RCTs published from 2002 to 2004 [25][26][27][28][29][30][31].…”

“…This upper value represents the cost of the most expensive statin that is currently available in Australia, namely atorvastatin. [22][23][24] Females: 1.88…”