Atorvastatin efficacy in the prevention of cardiovascular events in patients with diabetes mellitus and/or metabolic syndrome

Abstract

Several large-scale clinical trials have assessed the efficacy of atorvastatin in the primary and secondary prevention of cardiovascular events in patients with diabetes mellitus and/or metabolic syndrome. In primary prevention, CARDS (Collaborative Atorvastatin Diabetes Study) showed that atorvastatin 10 mg/day (vs placebo) reduced relative risk of the composite primary endpoint (acute coronary heart disease [CHD] events, coronary revascularisation, or stroke) by 37% (p = 0.001). This decrease was similar to decreases in major cardiovascular events in the ASCOT-LLA (Anglo-Scandinavian Cardiac Outcomes Trial-Lipid Lowering Arm) trial and HPS (Heart Protection Study). However, in CARDS, atorvastatin efficacy was evident as early as 6 months after starting treatment, whereas in HPS, simvastatin efficacy was noticeable only from about 15-18 months after starting treatment. In the ASCOT-LLA trial, in 2226 hypertensive diabetic patients without previous cardiovascular disease, atorvastatin (vs placebo) reduced the relative risk of all cardiovascular events and procedures by 25% (p = 0.038). In secondary prevention, substudies of the GREACE (GREek Atorvastatin and Coronary-heart-disease Evaluation), TNT (Treating to New Targets) and PROVE-IT (PRavastatin Or atorVastatin Evaluation and Infection Therapy) trials reported results for the approximately 15-25% of study participants who had diabetes. In the GREACE substudy, atorvastatin (vs physicians' standard care) significantly reduced the relative risk of total mortality by 52% (p = 0.049), coronary mortality by 62% (p = 0.042), coronary morbidity by 59% (p < 0.002) and stroke by 68% (p = 0.046). In the TNT substudy, incidence of the primary endpoint was significantly lower in diabetic patients treated with atorvastatin 80 mg/day rather than 10 mg/day (13.8% vs 17.9%; relative risk 0.75; p = 0.026). In the PROVE-IT substudy, a significantly lower incidence of acute cardiac events was reported for atorvastatin versus pravastatin recipients (21.1% vs 26.6%; p = 0.03) and, therefore, an absolute risk reduction of 5.5% was associated with atorvastatin therapy. ASPEN (Atorvastatin Study for Prevention of coronary heart disease Endpoints in Non-insulin-dependent diabetes mellitus) - a mixed primary and secondary prevention trial in diabetic patients - found that a 29% lower low-density lipoprotein-cholesterol level was seen with atorvastatin than placebo at endpoint (p < 0.0001); however, the reduction in composite primary endpoint of major cardiovascular events (cardiovascular mortality, nonfatal major cardiovascular event or stroke, and unstable angina requiring hospitalisation) with atorvastatin (13.7% vs 15.0% with placebo), and reduction in acute myocardial infarction relative risk of 27% with atorvastatin were not statistically significant. In CHD patients with metabolic syndrome (n = 5584) in a sub-analysis of the TNT trial, intensive versus lower-dosage atorvastatin therapy reduced the relative risk of major cardiovascular and cerebrovascular events by 29% (p < 0.0001). The analysis also revealed that CHD patients with, rather than those without, metabolic syndrome had a 44% greater level of absolute cardiovascular risk, thus clearly underscoring the clinical feasibility of administering intensive lipid-lowering therapy to CHD patients with metabolic syndrome. In summary, several patient populations, from definitive, large-scale studies, are now available to corroborate the integral place of atorvastatin--in line with various regional and internationally accepted disease management guidelines--in the primary and secondary prevention of cardiovascular events in patients with diabetes and/or metabolic syndrome.