New and emerging data from clinical trials of statins

Primary prevention in high-risk dyslipidemic patients without an established cardiovascular disease: Undertreatment and rationale for lipid-lowering therapy

BACKGROUND

Recent updated guidelines expand the usage of lipid-lowering therapy for primary prevention in high-risk individuals without an established cardiovascular disease (CVD). In contrast to secondary prevention, the extent of the target population and the utilization of lipid-lowering drugs are insufficiently clear. We examine the implementation of statin therapy as primary prevention in high-risk patients without a known CVD and discuss the rationale for the management of dyslipidemia in this population.

METHODS

Records of 371 consecutive patients without an established CVD who were hospitalized in an internal medicine department between January and June 2005 were evaluated for CVD-equivalent high-risk factors (diabetes mellitus, stroke of carotid origin, peripheral vascular disease, abdominal aortic aneurysm, or Framingham 10-year risk score >/=20%). Demographic and clinical data, in addition to lipid profile and usage of statin drugs prior to and during hospitalization, were analyzed.

RESULTS

Of the 371 non-cardiovascular patients, 88 (24%) were defined as high-risk individuals eligible for statin therapy as primary prevention of CVD. Their mean age was 71+/-11 years and their mean LDL-C level was 132+/-30 mg/dL. Seventeen patients (19%) were treated with statin drugs prior to admission and only two more patients (19/88, 22%) received statins in addition during hospitalization. Patients treated with statins had non-significantly higher LDL-C levels.

CONCLUSIONS

There is considerable undertreatment of high-risk patients without an established CVD with lipid-lowering drugs. There is also sub-optimal implementation of guidelines in clinical practice, despite well-established evidence of the benefits of statins in the primary prevention of CVD for high-risk individuals with average cholesterol levels, diabetes mellitus, and in elderly patients, as represented by our study population.

Cost-effectiveness of HMG-CoA reductase inhibitors in the treatment of dyslipidemia and prevention of CHD

The recent completion of several clinical trials of lipid-lowering therapy with 3-hydroxy-3-methylglutaryl coenzyme A inhibitors, or statins, was followed by an update in 2004 concerning the Adult Treatment Panel III guidelines issued by the National Cholesterol Education Program. Within this update, individuals considered at very high risk for coronary heart disease-related events were addressed, wherein the role of an aggressive, intensive lowering of lipid levels to new goals was presented. In achieving target cholesterol levels, the statins collectively represent first-line pharmacotherapeutic strategies, although each of the currently marketed agents differ in relative potency, dose, side effects and cost. As such, research concerning the pharmacoeconomics of lipid-lowering therapy may serve to augment clinical, evidence-based approaches to care. Furthermore, identifying and rectifying suboptimal care within healthcare systems may afford optimal outcomes amongst patients for resources consumed.

Effectiveness of statins for secondary prevention in elderly patients after acute myocardial infarction: an evaluation of class effect

BACKGROUND

Clinical trials have shown the benefits of statins after acute myocardial infarction (AMI). However, it is unclear whether different statins exert a similar effect in reducing the incidence of recurrent AMI and death when used in clinical practice.

METHODS

We conducted a retrospective cohort study (1997-2002) to compare 5 statins using data from medical administrative databases in 3 provinces (Quebec, Ontario and British Columbia). We included patients aged 65 years and over who were discharged alive after their first AMI-related hospital stay and who began statin treatment within 90 days after discharge. The primary end point was the combined outcome of recurrent AMI or death from any cause. The secondary end point was death from any cause. Adjusted hazard ratios (HRs) for each statin compared with atorvastatin as the reference drug were estimated using Cox proportional hazards regression analysis.

RESULTS

A total of 18,637 patients were prescribed atorvastatin (n = 6420), pravastatin (n = 4480), simvastatin (n = 5518), lovastatin (n = 1736) or fluvastatin (n = 483). Users of different statins showed similar baseline characteristics and patterns of statin use. The adjusted HRs (and 95% confidence intervals) for the combined outcome of AMI or death showed that each statin had similar effects when compared with atorvastatin: pravastatin 1.00 (0.90-1.11), simvastatin 1.01 (0.91-1.12), lovastatin 1.09 (0.95-1.24) and fluvastatin 1.01 (0.80-1.27). The results did not change when death alone was the end point, nor did they change after adjustment for initial daily dose or after censoring of patients who switched or stopped the initial statin treatment.

INTERPRETATION

Our results suggest that, under current usage, statins are equally effective for secondary prevention in elderly patients after AMI.

Statins and LDL-cholesterol lowering: an overview

Statins have become a cornerstone of treatment for dyslipidaemia primarily due to their marked lowering of low-density lipoprotein cholesterol (LDL-C). Studies show that statin treatment typically reduces relative risk of cardiovascular disease by 24-37%, regardless of age, sex, prior history of coronary heart disease (CHD), or other co-morbid conditions. There is also a growing body of evidence that statins can be effective in people whose LDL-C is not considered elevated under current guidelines. In both the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) and the Collaborative Atorvastatin Diabetes Study (CARDS), participants randomised to atorvastatin (10 mg/day) experienced at least a one-third reduction in major cardiovascular events, even though at baseline, their LDL-C was within the normal range. Other studies have also provided evidence that more intensive lipid-lowering regimens could provide additional clinical benefits. In the Reversal of Atherosclerosis with Aggressive Lipid Lowering (REVERSAL) trial, the first active-control clinical trial of CHD progression, an intensive lipid-lowering regimen using atorvastatin (80 mg/day) decreased atherogenic lipoproteins and atheroma volume in patients with established CHD, compared with a moderate regimen using pravastatin (40 mg/day). Furthermore, relative to baseline, there was no measurable atheroma progression in the atorvastatin group. While statin therapy does offer significant clinical benefit, 60-70% of major cardiovascular events are still not prevented, which underscores the need for alternative interventions. Targeting inflammatory mediators of atherosclerosis such as C-reactive protein (CRP), as well as combination therapy to simultaneously raise high-density lipoprotein cholesterol (HDL-C) and lower LDL-C, are among the promising new strategies for primary and secondary prevention of atherosclerotic disease. This article will summarise data concerning use of statins in patients without markedly elevated LDL-C. The issue of the ideal LDL-C target will also be considered before addressing future treatment options for dyslipidaemia.

Treating low HDL—From bench to bedside

The inverse relationship between the plasma high-density lipoprotein cholesterol (HDL-C) and the risk of coronary heart disease (CHD) is well recognized in the general population. However, the development of effective therapeutics targeting HDL continues to be challenging, which is due in part to the heterogeneity of its structure and composition and the complexity of its metabolism. In this paper, we review a number of recent advances in our understanding of HDL metabolism and its role in atherogenesis. We discuss the HDL-C raising effect of a selected number of currently available lipid-modifying drugs and on a selected number of novel HDL-targeted therapeutic strategies under development.

Intensive versus moderate lipid lowering with statins after acute coronary syndromes

BACKGROUND

Lipid-lowering therapy with statins reduces the risk of cardiovascular events, but the optimal level of low-density lipoprotein (LDL) cholesterol is unclear.

METHODS

We enrolled 4162 patients who had been hospitalized for an acute coronary syndrome within the preceding 10 days and compared 40 mg of pravastatin daily (standard therapy) with 80 mg of atorvastatin daily (intensive therapy). The primary end point was a composite of death from any cause, myocardial infarction, documented unstable angina requiring rehospitalization, revascularization (performed at least 30 days after randomization), and stroke. The study was designed to establish the noninferiority of pravastatin as compared with atorvastatin with respect to the time to an end-point event. Follow-up lasted 18 to 36 months (mean, 24).

RESULTS

The median LDL cholesterol level achieved during treatment was 95 mg per deciliter (2.46 mmol per liter) in the standard-dose pravastatin group and 62 mg per deciliter (1.60 mmol per liter) in the high-dose atorvastatin group (P<0.001). Kaplan-Meier estimates of the rates of the primary end point at two years were 26.3 percent in the pravastatin group and 22.4 percent in the atorvastatin group, reflecting a 16 percent reduction in the hazard ratio in favor of atorvastatin (P=0.005; 95 percent confidence interval, 5 to 26 percent). The study did not meet the prespecified criterion for equivalence but did identify the superiority of the more intensive regimen.

CONCLUSIONS

Among patients who have recently had an acute coronary syndrome, an intensive lipid-lowering statin regimen provides greater protection against death or major cardiovascular events than does a standard regimen. These findings indicate that such patients benefit from early and continued lowering of LDL cholesterol to levels substantially below current target levels.