LDL-Cholesterol and the Potential for Coronary Risk Improvement

Aim: To determine population-attributable predicted coronary risk for major coronary risk factors and derive potential for reduction of global coronary risk. Methods: We obtained images of carotid atherosclerosis in practice-based subjects from self-referred CORDICARE (COR) and physician-referred KARDIOLAB (KAR) patients and calculated 10-year predicted coronary risk according t o Swiss guidelines (AGLA) and via reclassification by post-test risk derived from ultrasound-measured total plaque area of the left and right carotid artery. We calculated predicted coronary risk reduction attributable to achievement of all AGLA goals, and for individual risk factors: smokers became nonsmokers, diabetic patients became nondiabetic patients, HDL level, if not already attained, was increased to 1.5 mmol/l, similarly, LDL level was lowered to 1.8 mmol/l, systolic blood pressure (BP) was lowered to 130 and then 10-year risk was recalculated for every subject. Results: COR included N = 900 (48% female), mean age 59 ± 9 years, KAR included N = 600 (35% female), mean age 58 ± 9 years. COR vs KAR: fewer smokers (12% vs 28%), fewer diabetic patients (3% vs 9%), higher systolic BP (133 ± 15 vs 128 ± 19) and higher HDL (1.6 ± 0.4 vs 1.4 ± 0.4 mmol/l), lower AGLA coronary risk (6.6 ± 7.0 vs 8.1 ± 8.6%), lower post-test risk (13.4 ± 14.1 vs 16.2 ± 16.4%). Predicted percent risk reductions for COR and KAR were: all AGLA treatment goals reached (–46% vs –51%), AGLA LDL goals met (–29% vs –29%), LDL ≤1.8 mmol/l (–52% vs –49%), no smokers (–7% vs –12%), HDL 1.50 mmol/l (–13% vs –21%), blood pressure ≤130 (–7% vs –6%), no diabetes (–1% vs –3%). Conclusions: Achieving LDL ≤1.8 mmol/l would be the single most important intervention in lowering coronary risk by 50%. In reaching all AGLA goals, the predicted 10-year risk would fall from 13–7% in COR and from 16–8% in KAR. Subjects are predominantly at low risk according to AGLA, at intermediate risk after reclassification, and could become true low risk through intensified intervention.