Effects of adding fenofibrate (200 mg/day) to simvastatin (10 mg/day) in patients with combined hyperlipidemia and metabolic syndrome

Update on the clinical utility of fenofibrate in mixed dyslipidemias: mechanisms of action and rational prescribing

Mixed dyslipidemia is a common lipid disorder characterized by the presence of an atherogenic lipoprotein phenotype due to abnormalities in various atherogenic and anti-atherogenic lipoproteins. Despite the link between the decrease of LDL-cholesterol by statin treatment and the prevention of cardiovascular disease, a high residual risk is observed in statin trials. This residual risk is partly explained by lipoprotein abnormalities other than LDL. Fenofibrate exerts a favorable effect on the atherogenic lipid profile of mixed dyslipidemia and can effectively reduce cardiovascular disease in patients with mixed dyslipidemia. Fenofibrate may offer important treatment alternatives as a second-line therapy in several circumstances: in combination with a statin for patients with mixed dyslipidemias not at goals on statin mono-therapy; in monotherapy for patients intolerant or with contraindication to statin therapy; and in combination with other drugs (ezetimibe, colesevelam) for patients with mixed dyslipidemias, known intolerance, or contraindication to statin and not at goals on fenofibrate monotherapy. However, the role of fenofibrate-statin therapy and of other therapies involving fenofibrate in cardiovascular risk reduction strategies remains to be established.

Efficacy and safety of ABT-335 (fenofibric acid) in combination with atorvastatin in patients with mixed dyslipidemia

In patients with mixed dyslipidemia characterized by increased triglycerides (TG), decreased high-density lipoprotein (HDL) cholesterol, and increased low-density lipoprotein (LDL) cholesterol, monotherapy with lipid-altering drugs often fails to achieve all lipid targets. This multicenter, double-blind, active-controlled study evaluated ABT-335 (fenofibric acid) in combination with 2 doses of atorvastatin in patients with mixed dyslipidemia. A total of 613 patients with LDL cholesterol > or =130 mg/dl, TG > or =150 mg/dl, and HDL cholesterol <40 mg/dl for men and <50 mg/dl for women were randomly assigned to ABT-335 (135 mg), atorvastatin (20, 40, or 80 mg), or combination therapy (ABT-335 + atorvastatin 20 or 40 mg) and treated for 12 weeks. Combination therapy with ABT-335 + atorvastatin 20 mg resulted in significantly greater improvements in TG (-45.6% vs -16.5%) and HDL cholesterol (14.0% vs 6.3%) compared with atorvastatin 20 mg and LDL cholesterol (-33.7% vs -3.4%) compared with ABT-335. Similarly, significantly greater improvements were observed with ABT-335 + atorvastatin 40 mg in TG (-42.1% vs -23.2%) and HDL cholesterol (12.6% vs 5.3%) compared with atorvastatin 40 mg and LDL cholesterol (-35.4% vs -3.4%) compared with ABT-335 monotherapy. Combination therapy also improved multiple secondary variables. Combination therapy was generally well tolerated with a safety profile consistent with those of ABT-335 and atorvastatin monotherapies. No rhabdomyolysis was reported. In conclusion, ABT-335 + atorvastatin combination therapy resulted in more effective control of multiple lipid parameters than either monotherapy and may be an appropriate therapy for patients with mixed dyslipidemia.

Fenofibrate: treatment of hyperlipidemia and beyond

Fenofibrate is a PPAR-alpha agonist indicated for the treatment of hypertriglyceridemia and mixed dyslipidemia, and is approved for the treatment of hypercholesterolemia, lipid abnormalities commonly observed in patients at high risk of cardiovascular disease, including Type 2 diabetes and/or metabolic syndromes. Treatment with fenofibrate lowers triglycerides, raises HDL-cholesterol and decreases concentrations of small LDL-cholesterol particles and apolipoprotein B. Fenofibrate is particularly effective for reducing postprandial VLDL and LDL particle concentrations, and the increased oxidative stress and inflammatory response that occurs after a fatty meal. In addition, nonlipid pleiotropic effects mediated by PPAR-alpha are likely to contribute to the reduction in atherosclerosis progression and cardiovascular events, and have beneficial effects on diabetes-related microvascular diseases. While current approaches to treating dyslipidemia to prevent cardiovascular diseases focus on statin therapy, it is increasingly clear that substantial residual risk persists. The clinical significance of combination therapy with fenofibrate and a statin to macrovascular and microvascular risk is being evaluated in a large outcomes study.

Efficacy and safety of ABT-335 (fenofibric acid) in combination with simvastatin in patients with mixed dyslipidemia: a phase 3, randomized, controlled study

BACKGROUND

Patients with mixed dyslipidemia often require combination therapy to effectively control lipid abnormalities. This study compared the effects of combination therapy with ABT-335 (a new formulation of fenofibric acid) and simvastatin to ABT-335 and simvastatin monotherapies on lipid and nonlipid parameters in patients with mixed dyslipidemia.

METHODS

This was a phase 3, multicenter, randomized, double-blind, active-controlled study. A total of 657 patients with mixed dyslipidemia (low-density lipoprotein cholesterol [LDL-C] > or =130 mg/dL, triglycerides [TGs] > or =150 mg/dL, and high-density lipoprotein cholesterol [HDL-C]<40 mg/dL [men] or <50 mg/dL [women]) were randomized to 12 weeks of treatment with ABT-335 + simvastatin (20 or 40 mg) combination therapy, ABT-335 monotherapy (135 mg), or simvastatin monotherapy (20, 40, or 80 mg).

RESULTS

Combination therapy resulted in significantly greater increases in HDL-C and decreases in TGs compared to the corresponding simvastatin monotherapy dose (P < .001) and decreases in LDL-C compared to ABT-335 monotherapy (P < .001). HDL-C increased 17.8% versus 7.2% and TGs decreased -37.4% versus -14.2% (ABT-335 + simvastatin 20 vs simvastatin 20); LDL-C decreased -24.0% versus -4.0% (ABT-335 + simvastatin 20 vs ABT-335). HDL-C increased 18.9% versus 8.5% and TGs decreased -42.7% versus -22.4% (ABT-335 + simvastatin 40 vs simvastatin 40); LDL-C decreased -25.3% versus -4.0% (ABT-335 + simvastatin 40 vs ABT-335). Twelve-week treatment with combination therapy was generally well tolerated with a safety profile consistent with ABT-335 and simvastatin monotherapies. No cases of rhabdomyolysis were reported.

CONCLUSION

For patients with mixed dyslipidemia, combination therapy provided more effective control of multiple lipid parameters than either monotherapy alone, with a safety profile similar to both monotherapies.

A review of the current status of the management of mixed dyslipidemia associated with diabetes mellitus and metabolic syndrome

Current treatment guidelines recommend lowering elevated low-density lipoprotein (LDL) cholesterol levels with a statin as the primary lipid-modifying intervention to reduce cardiovascular risk in patients with type 2 diabetes mellitus or metabolic syndrome. However, even with high-dose statin therapy or the combination of statin plus ezetimibe, many patients remain at substantial risk of a cardiovascular event. Increasingly, there is recognition of the importance of treating all components of the atherogenic dyslipidemic profile associated with both conditions, specifically low high-density lipoprotein cholesterol and elevated triglyceride levels, in addition to lowering LDL cholesterol. Both niacin (nicotinic acid) and fibrates are recommended as options for combination with a statin in this setting. Data from ongoing prospective outcomes studies are needed to evaluate the efficacy and safety of these combinations.

Treatment of hyperlipidaemia with fenofibrate and related fibrates

BACKGROUND

Fenofibrate is the most widely used fibrate. Its efficacy and tolerability in the treatment of hypertriglyceridaemia and combined hyperlipidaemia have been demonstrated in several clinical trials.

OBJECTIVE

To review the pharmacology, lipid-lowering and extra-lipid effects of fenofibrate and to preview ABT-335, an investigational new fenofibric acid molecule.

RESULTS

The effects of fenofibrate are mediated through the active metabolite fenofibric acid, and are described in detail in the paper. ABT-335 is a salt of fenofibric acid and, unlike fenofibrate, does not require first pass metabolism to the active moiety. ABT-335 is being developed for combination use with statins, and has recently completed three large Phase III randomised controlled trials in which the efficacy and safety of ABT-335 in combination with the three most commonly prescribed statins, atorvastatin, simvastatin and rosuvastatin, was evaluated in patients with mixed dyslipidaemia.

CONCLUSION

ABT-335 in combination with statins may provide a safe and efficacious treatment modality that enables achievement of several therapeutic goals in patients with mixed dyslipidaemia who have high cardiovascular risk.

High density lipoprotein cholesterol: an evolving target of therapy in the management of cardiovascular disease

Since the pioneering work of John Gofman in the 1950s, our understanding of high density lipoprotein cholesterol (HDL-C) and its relationship to coronary heart disease (CHD) has grown substantially. Numerous clinical trials since the Framingham Study in 1977 have demonstrated an inverse relationship between HDL-C and one’s risk of developing CHD. Over the past two decades, preclinical research has gained further insight into the nature of HDL-C metabolism, specifically regarding the ability of HDL-C to promote reverse cholesterol transport (RCT). Recent attempts to harness HDL’s ability to enhance RCT have revealed the complexity of HDL-C metabolism. This review provides a detailed update on HDL-C as an evolving therapeutic target in the management of cardiovascular disease.

Activation of peroxisome proliferator-activated receptor-alpha in mice induces expression of the hepatic low-density lipoprotein receptor

Background and purpose:

Mutations in the low-density lipoprotein receptor (LDLR) gene cause familial hypercholesterolaemia in humans and deletion of the LDLR induces lesion development in mice fed a high-fat diet. LDLR expression is predominantly regulated by sterol regulatory element-binding protein 2 (SREBP2). Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) ligand, belongs to a drug class used to treat dyslipidaemic patients. We have investigated the effects of fenofibrate on hepatic LDLR expression.

Experimental approach:

The effects of fenofibrate on hepatic LDLR expression (mRNA and protein) and function were evaluated by both in vitro (with AML12 cells) and in vivo experiments in mice.

Key results:

Fenofibrate increased LDLR expression and LDL binding in a mouse hepatoma cell line, AML12 cells. Fenofibrate restored sterol-inhibited hepatocyte LDLR expression. Mechanistic studies demonstrated that induction of LDLR expression by fenofibrate was dependent on PPARα and sterol regulatory elements (SRE). Specifically, fenofibrate induced LDLR expression by increasing maturation of SREBP2 and phosphorylation of protein kinase B (Akt) but had no effect on SREBP cleavage-activating protein. In vivo, a high-fat diet suppressed LDLR expression in mouse liver while elevating total and LDL cholesterol levels in plasma. However, fenofibrate restored LDLR expression inhibited by high-fat diets in the liver and reduced LDL cholesterol levels in plasma.

Conclusions and implications:

Our data suggest that fenofibrate increased hepatic LDLR expression in mice by a mechanism involving Akt phosphorylation and LDLR gene transcription mediated by SREBP2.

Combination therapy with fenofibrate, a peroxisome proliferator-activated receptor alpha agonist, and simvastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor, on experimental traumatic brain injury

We and others have demonstrated that fibrates [peroxisome proliferator-activated receptor (PPAR)alpha agonists] and statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) exerted neuroprotective and pleiotropic effects in experimental models of traumatic brain injury (TBI). Because the combination of statins and fibrates synergistically enhanced PPARalpha activation, we hypothesized that the combination of both drugs may exert more important and/or prolonged beneficial effects in TBI than each alone. In this study, we examined the combination of fenofibrate with simvastatin, administered 1 and 6 h after injury, on the consequences of TBI. First, our dose-effect study demonstrated that the most efficient dose of simvastatin (37.5 mg/kg) reduced post-traumatic neurological deficits and brain edema. Then, the effects of the combination of fenofibrate (50 mg/kg) and simvastatin (37.5 mg/kg), given p.o. at 1 and 6 h after TBI, were evaluated on the TBI consequences in the early and late phase after injury. The combination exerted more sustained neurological recovery-promoting and antiedematous effects than monotherapies, and it synergistically decreased the post-traumatic brain lesion. Furthermore, a delayed treatment given p.o. at 3 and 8 h after TBI with the combination was still efficient on neurological deficits induced by TBI, but it failed to reduce the brain edema at 48 h. The present data represent the first demonstration that the combination of fenofibrate and simvastatin exerts prolonged and synergistic neuroprotective effects than each drug alone. Thus, these results may have important therapeutic significance for the treatment of TBI.

Vascular and metabolic effects of treatment of combined hyperlipidemia: focus on statins and fibrates

Combined hyperlipidemia results from overproduction of hepatically synthesized apolipoprotein B in very low-density lipoproteins in association with reduced lipoprotein lipase activity. Thus, this condition is typically characterized by concurrent elevations in total cholesterol and triglycerides with decreased high-density lipoprotein cholesterol. High levels of apolipoprotein B-containing lipoproteins, most prominently carried by low-density lipoprotein (LDL) particles, are an important risk factor for coronary heart disease. Statin therapy is highly effective at lowering LDL cholesterol. Despite the benefits of statin treatment for lowering total and LDL cholesterol, many statin-treated patients still have initial or recurrent coronary heart disease events. In this regard, combined therapy with statins and fibrates is more effective in controlling atherogenic dyslipidemia in patients with combined hyperlipidemia than either drug alone. Furthermore, statins and fibrates activate PPARalpha in a synergistic manner providing a molecular rationale for combination treatment in coronary heart disease. Endothelial dysfunction associated with cardiovascular diseases may contribute to insulin resistance so that there may also be additional beneficial metabolic effects of combined statin/fibrates therapy. However, there has been little published evidence that combined therapy is synergistic or even better than monotherapy alone in clinical studies. Therefore, there is a great need to study the effects of combination therapy in patients. When statins are combined with gemfibrozil therapy, this is more likely to be accompanied by myopathy. However, this limitation is not observed when fenofibrate, bezafibrate, or ciprofibrate are used in combination therapy.

The clinical significance of the size of low-density-lipoproteins and the modulation of subclasses by fibrates

BACKGROUND

Beyond total low-density-lipoproteins (LDL) levels, increasing evidence suggests that the 'quality' of LDL exerts a great influence on the cardiovascular risk. Several studies have also shown that the therapeutic modulation of LDL size is of benefit in reducing the risk of cardiovascular events. Hypolipidaemic treatment is able to alter LDL subclass distribution but strong variations have been noticed among different agents. Fibrates have a major impact on triglyceride metabolism and in modulating LDL size and subclasses, but variations exist among the different molecules.

METHODOLOGY

A literature search (by Medline and Scopus) was performed using the following headings: 'small dense LDL', 'LDL size', 'LDL subfractions', 'LDL subclasses', 'LDL distribution' and 'fenofibrate', 'bezafibrate', 'ciprofibrate' and 'gemfibrozil' up to 20 January 2007. The authors also manually reviewed the references of selected articles for any pertinent material.

RESULTS

Analysis of all published studies revealed that treatment with fenofibrate, ciprofibrate, bezafibrate and gemfibrozil is usually beneficial, and fenofibrate may be more efficacious than the other molecules. This is supported by using all the available techniques in subjects with a very wide range of lipid alterations.

CONCLUSION

Among the different agents, fenofibrate has been found to be particularly effective in modulating LDL size and subclasses in patients at higher cardiovascular risk, such as those with type 2 diabetes or the metabolic syndrome.

Inflammation in diabetes mellitus: role of peroxisome proliferator-activated receptor-alpha and peroxisome proliferator-activated receptor-gamma agonists

Patients with type 2 diabetes mellitus and/or the metabolic syndrome have considerable cardiovascular risk. Treatment with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) and with antihypertensive and some antihyperglycemic agents reduces this risk, but residual macrovascular morbidity and mortality persist, even in patients assigned to intensive multifactorial intervention programs. Therapeutic strategies that target inflammation and lipid abnormalities not well addressed by statins may offer additional opportunities for improving the prognosis of these patients. Inflammation, a key mechanism of atherogenesis, appears to have particular relevance to diabetic vascular complications, as well as in the development of diabetes itself. Oxidative stress and hyperglycemia also figure among the pathogenic factors that promote cardiovascular complications in patients with the metabolic syndrome and/or diabetes and may augment the ongoing inflammation. Peroxisome proliferator-activated receptor (PPAR)-alpha and PPAR-gamma, members of the nuclear receptor family, form ligand-activated transcription factors that regulate key important metabolic pathways. PPARs have become therapeutic targets through the use of the fibrate class of antidyslipidemic drugs (PPAR-alpha) and the insulin-sensitizing thiazolidinediones (PPAR-gamma). The activation of these PPARs may also suppress inflammation and atherosclerosis. Recent clinical trials (Fenofibrate Intervention and Event Lowering in Diabetes [FIELD], Prospective Pioglitazone Clinical Trial in Macrovascular Events [PROactive]) have considered the impact of these PPAR agonists on cardiovascular disease, with mixed effects that require careful analysis, especially given ongoing trials and additional PPAR agonists in development.

Effects of peroxisome proliferator-activated receptors on lipoprotein metabolism and glucose control in type 2 diabetes mellitus

Peroxisome proliferator-activated receptors (PPARs) are central regulators of lipoprotein metabolism and glucose homeostasis that are considered particularly useful for improving glycemic control and comorbidities in patients with type 2 diabetes mellitus. Clinical trials of PPAR-alpha agonists have demonstrated efficacy in reducing cardiovascular events; however, these benefits have been confined to subgroups of patients with low levels of high-density lipoprotein cholesterol or high levels of triglycerides. While activators of PPAR-gamma reduce early atherosclerotic lesions and reduce cardiovascular events, these agents have the effect of increasing fluid retention in patients, which results in more hospitalizations for congestive heart failure. Future studies of PPAR-gamma agonists or dual PPAR-alpha/gamma agonists will require further delineation of the risk profile to avoid adverse outcomes in susceptible patients.

Fenofibrate

Fenofibrate is a fibric acid derivative indicated for use in the treatment of primary hypercholesterolaemia, mixed dyslipidaemia and hypertriglyceridaemia in adults who have not responded to nonpharmacological measures. Its lipid-modifying effects are mediated by activation of peroxisome proliferator-activated receptor-alpha. Fenofibrate also has nonlipid (i.e. pleiotropic) effects (e.g. it reduces fibrinogen, C-reactive protein and uric acid levels and improves flow-mediated dilatation). Fenofibrate improves lipid levels (in particular triglyceride [TG] and high-density lipoprotein-cholesterol [HDL-C] levels) in patients with primary dyslipidaemia. Its lipid-lowering profile means that fenofibrate is particularly well suited for use in atherogenic dyslipidaemia (characterised by high TG levels, low HDL-C levels and small, dense low-density lipoprotein [LDL] particles), which is commonly seen in patients with the metabolic syndrome and type 2 diabetes mellitus. Indeed, fenofibrate improves the components of atherogenic dyslipidaemia in patients with these conditions, including a shift from small, dense LDL particles to larger, more buoyant LDL particles. Greater improvements in lipid levels are seen when fenofibrate is administered in combination with an HMG-CoA reductase inhibitor (statin) or in combination with ezetimibe, compared with monotherapy with these agents. In the DAIS study, fenofibrate significantly slowed the angiographic progression of focal coronary atherosclerosis in patients with type 2 diabetes. In terms of clinical outcomes, although no significant reduction in the risk of coronary events was seen with fenofibrate in the FIELD trial in patients with type 2 diabetes, treatment was associated with a significantly reduced risk of total cardiovascular disease (CVD) events, primarily through the prevention of non-fatal myocardial infarction and coronary revascularisation. Subgroup analyses revealed significant reductions in total CVD events and coronary heart disease events in patients with no previous CVD, suggesting a potential role for primary prevention with fenofibrate in patients with early type 2 diabetes. Improvements were also seen in microvascular outcomes with fenofibrate in the FIELD trial. Fenofibrate is generally well tolerated, both as monotherapy and when administered in combination with a statin. Combination therapy with fenofibrate plus a statin appears to be associated with a low risk of rhabdomyolysis; no cases of rhabdomyolysis were reported in patients receiving such therapy in the FIELD trial. Thus, fenofibrate is a valuable lipid-lowering agent, particularly in patients with atherogenic dyslipidaemia.

Management of dyslipidemia in diabetes

Diabetes is associated with a high risk of cardiovascular disease. The management of dyslipidemia, a well-recognized and modifiable risk factor among patients with type 2 diabetes, is an important element in the multifactorial approach to prevent coronary heart disease. Diabetic dyslipidemia typically consists of elevated triglyceride, low high-density lipoprotein cholesterol (HDL-C), and the predominance of small dense low-density lipoprotein (LDL) particles. LDL cholesterol (LDL-C) levels in patients with diabetes are similar to those found in the rest of the population. During the past few years, clinical trials have provided evidence that lipid-lowering therapy has a similar beneficial effect on cardiovascular outcomes in diabetic and nondiabetic individuals. According to current guidelines, the primary lipid target is an LDL-C <100 mg/dL (<70 mg/dL in very high-risk patients) and, to this end, statins are the agents of choice. The appropriate management of dyslipidemia in patients with diabetes, particularly in individuals with low LDL-C, remains controversial. To achieve lipid targets, attention should be directed first toward nonpharmacologic therapeutic interventions to control dyslipidemia, such as diet, exercise, smoking cessation, weight loss, and glycemic control. Statin therapy is recommended for most subjects but, frequently, a combination of lipid-lowering agents is required. A number of combinations are possible, and several factors should be considered to improve the safety of this strategy.

The Clinical Relevance of Low-Density-Lipoproteins Size Modulation by Statins

The predominance of small, dense low density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III; in fact, LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease. Several studies have also shown that the therapeutical modulation of LDL size is of great benefit in reducing the risk of cardiovascular events. Hypolipidemic treatment is able to alter LDL subclass distribution and statins are currently the most widely used lipid-lowering agents. Statins are potent inhibitors of hydroxy-methyl-glutaryl-coenzyme A reductase, the rate-limiting enzyme in hepatic cholesterol synthesis and are the main drugs of choice for the treatment of elevated plasma LDL cholesterol concentrations. Statins potentially lower all LDL subclasses (e.g., large, medium and small particles); thus, their net effect on LDL subclasses or size is often only moderate. However, a strong variation has been noticed among the different agents: analyses of all published studies suggest a very limited role of pravastatin and simvastatin in modifying LDL size and their subclasses, while fluvastatin and atorvastatin seem to be much more effective agents. Finally, rosuvastatin, the latest statin molecule introduced in the market, seems to be promising in altering LDL subclasses towards less atherogenic particles.

Hypolipidemic therapy for the metabolic syndrome

The metabolic syndrome appears to affect a significant proportion of the population and is associated with increased risk for development of cardiovascular disease as well as of type-2 diabetes. No single treatment for the metabolic syndrome as a whole yet exists. While the primary management of patients with the metabolic syndrome involves healthy lifestyle promotion, the atherogenic dyslipidemia is a primary target for cardiovascular disease risk reduction in these patients. Statin therapy provides effective reduction of LDL-cholesterol, which represents the primary therapeutic goal of lipid-lowering therapy in patients at risk for cardiovascular disease. Fibrates in turn are effective in normalizing lipid levels (mainly triglycerides and HDL-cholesterol) in patients with the metabolic syndrome and may improve insulin resistance. Whereas statins remain the drug of choice for patients who need to achieve the LDL-cholesterol goal, fibrate therapy may represent an alternative for those with low HDL-cholesterol and high triglyceride levels. The simultaneous use of fibrates could be indicated in patients whose LDL-cholesterol is controlled by statin therapy but whose HDL-cholesterol and/or triglycerides are still inappropriate. Such a combination, however, needs careful monitoring due to the potential hazard of adverse drug interactions. Nicotinic acid and ezetimibe may be useful agents for therapy, particularly when combined with statins. A number of emerging therapies offer potential as future options for the pharmacological treatment of metabolic syndrome.

Drug therapy of the metabolic syndrome: minimizing the emerging crisis in polypharmacy

The metabolic syndrome--a collection of factors associated with increased risk for cardiovascular disease and diabetes--is becoming increasingly common, largely as a result of the increase in the prevalence of obesity. Although it is generally agreed that first-line clinical intervention for the metabolic syndrome is lifestyle change, this is insufficient to normalize the risk factors in many patients, and so residual risk could be high enough to justify drug therapy. However, at present there are no approved drugs that can reliably reduce all of the metabolic risk factors over the long term, and so there is growing interest in therapeutic strategies that might target multiple risk factors more effectively, thereby minimizing problems with polypharmacy. This review summarizes current understanding of the nature of the metabolic syndrome, and discusses each of the risk factors of the metabolic syndrome as possible primary drug targets; potential secondary or tertiary targets are also considered.

The metabolic syndrome: prevalence, CHD risk, and treatment

An increased risk of coronary heart disease (CHD) morbidity and mortality is associated with the metabolic syndrome, a condition characterized by the concomitant presence of several abnormalities, including abdominal obesity, dyslipidemia, hypertension, insulin resistance (with or without glucose intolerance or diabetes), microalbuminuria, prothrombotic, and proinflammatory states. Estimates of the prevalence of the metabolic syndrome indicate that this condition is now common and likely to increase dramatically over the coming decades, in parallel with greater rates of obesity and Type 2 diabetes. Risk factors for the metabolic syndrome are already present in obese children and adolescents. Thus, identifying and treating all affected individuals promptly and optimally are critical to ensure that this potentially challenging healthcare burden is minimized. Here, we review the prevalence of the metabolic syndrome, dyslipidemias, and CHD risk. Although changes in lifestyle are fundamental to reducing many of the CHD risk factors associated with the metabolic syndrome, pharmacologic interventions also play an important role. Retrospective subanalyses of the effects of statins on coronary event rates and lipid levels in patients with the metabolic syndrome included in clinical trials indicate that these agents are beneficial in correcting the extensive lipid abnormalities that are frequently present in these individuals. However, the optimal management of metabolic syndrome dyslipidemia will depend on the outcomes of future prospective clinical trials. This review examines the underlying causes and prevalence of the metabolic syndrome and its impact on CHD morbidity and mortality and discusses the role of statins in optimizing its management.

Evaluation of the potential for pharmacokinetic interaction between fenofibrate and ezetimibe: A phase I, open-label, multiple-dose, three-period crossover study in healthy subjects

OBJECTIVE

This study was conducted to evaluate the potential for pharmacokinetic interaction between fenofibrate and ezetimibe in healthy subjects.

METHODS

This was a Phase I, open-label, multiple-dose,3-period crossover study conducted in healthy adult men and women. Subjects received fenofibrate 145 mg alone, fenofibrate 145 mg with ezetimibe 10 mg, and ezetimibe 10 mg alone for 10 consecutive days, in an order determined by computerized randomization schedule. Blood samples were collected for up to 24 hours after dosing on study day 1 and up to 120 hours after dosing on study day 10 for determination of plasma concentrations of fenofibric acid, unconjugated (free) ezetimibe, and total (conjugated and unconjugated) ezetimibe using validated high-performance liquid chromatography methods with mass-spectrometric detection. Ezetimibe glucuronide concentrations were estimated by subtracting free ezetimibe concentrations from total ezetimibe concentrations.

RESULTS

Eighteen healthy adults (12 men, 6 women; 17 white, 1 black) were enrolled in the study. Their mean age was 43.4 years (range, 27-55 years), their mean weight 78.7 kg (range, 60-98 kg), and their mean height 174.9 cm (range, 156-194 cm). Coadministration of multiple doses of fenofibrate and ezetimibe produced no statistically significant effect on the pharmacokinetics of fenofibric acid but significantly increased exposures to total ezetimibe and ezetimibe glucuronide (P < 0.05). Using point estimates, co-administration of fenofibrate and ezetimibe increased AUC central values for total ezetimibe and ezetimibe glucuronide by 43% (90% CI, 29-59) and 49% (90% CI, 34-65), respectively.

CONCLUSION

In these healthy volunteers, coadministration of multiple doses of fenofibrate and ezetimibe had no statistically significant effect on the pharmacokinetics of fenofibric acid but was associated with a significant increase in exposure to total ezetimibe and its metabolite ezetimibe glucuronide.

The effect of simvastatin on triglyceride-rich lipoproteins in patients with type 2 diabetic dyslipidemia: a SILHOUETTE trial sub-study

OBJECTIVE

To determine if simvastatin effectively decreases the elevated levels of triglyceride (TG), TG-rich lipoproteins, and small, dense LDL particles, which are characteristic of diabetic dyslipidemia.

RESEARCH DESIGN AND METHODS

We conducted a prespecified analysis from a double-blind, placebo-controlled, randomized, 6-week crossover trial in patients with type 2 diabetes and low HDL-C (< 40 mg/dL). Each patient was randomized to 1 of 6 possible treatment arms; each patient received simvastatin 80 mg, simvastatin 40 mg, and placebo over 3 periods. We used the validated vertical auto profile (VAP) method to directly assess TG-rich lipoproteins and LDL subclasses. We assessed the efficacy of simvastatin to improve the lipoprotein profile in adult men (71%) and women (29%) (n = 151) with stable type 2 diabetes (HbA1C < 9%), LDL-C > 100 mg/dL, HDL-C < 40 mg/dL, and fasting TG level > 150 and < 700 mg/dL (median = 273 mg/dL).

MAIN OUTCOME MEASURES

Percentage change from baseline in IDL and VLDL (TG-rich lipoproteins), LDL subclasses, and additional lipoproteins at the end of each 6-week treatment interval; percentage of patients who reached NCEP ATP III non-HDL goal of < 130 mg/dL by the end of each 6-week period.

RESULTS

Both simvastatin 80 mg and 40 mg significantly reduced VLDL-C, VLDL3, and IDL, as well as the four LDL subclasses measured with VAP, compared with placebo. Simvastatin 80 mg, compared with simvastatin 40 mg, provided additional efficacy. With simvastatin 80 mg, 77.2% of patients not at their non-HDL-C goal of < 130 mg/dL at study baseline reached goal, compared with 65.7% following simvastatin 40 mg treatment, and 2.2% following placebo.

CONCLUSIONS

Treatment with simvastatin effectively reduced the elevated levels of TG-rich lipoproteins and improved LDL composition in patients with type 2 diabetes. A large percentage of these patients attained the NCEP ATP III non-HDL-C goal of < 130 mg/dL, which demonstrates the improvement of the atherogenic profile in these patients.

Should all patients with metabolic syndrome be treated with statins?

The metabolic syndrome is a constellation of cardiovascular risk factors that include atherogenic dyslipidemia, elevated blood pressure, abdominal/truncal obesity, and glucose intolerance. Current National Cholesterol Education Program (NCEP) recommendations for specific treatment of the metabolic syndrome are centered on therapeutic lifestyle changes. A recent publication from the NCEP Adult Treatment Panel III suggests pharmacologic intervention for parameters of metabolic syndrome, including dyslipidemia, hypertension, and hyperglycemia, to prevent cardiovascular disease, based on risk category. This review looks at the clinical trial evidence to support the use of statins in metabolic syndrome.

Fenofibrate: a novel formulation (Triglide) in the treatment of lipid disorders: a review

Cardiovascular disease is the major cause of mortality worldwide and accounts for approximately 40% of all deaths. Dyslipidemia is one of the primary causes of atherosclerosis and effective interventions to correct dyslipidemia should form an integral component of any strategy aimed at preventing cardiovascular disease. Fibrates have played a major role in the treatment of hyperlipidemia for more than two decades. Fenofibrate is one of the most commonly used fibrates worldwide. Since fenofibrate was first introduced in clinical practice, a major drawback has been its low bioavailability when taken under fasting conditions. Insoluble Drug Delivery-Microparticle fenofibrate is a new formulation that has an equivalent extent of absorption under fed or fasting conditions. In this review, we will discuss the clinical pharmacology of fenofibrate, with particular emphasis on this novel formulation, as well as its lipid-modulating and pleiotropic actions. We will also analyze the major trial that evaluated fibrates for primary and secondary prevention of cardiovascular disease, the safety and efficacy profile of fibrate-statin combination treatment, and the current recommendations regarding the use of fibrates in clinical practice.

Low-density lipoprotein size and cardiovascular risk assessment

A predominance of small, dense low-density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease and evidences suggests that both quality (particularly small, dense LDL) and quantity may increase cardiovascular risk. However, other authors have suggested that LDL size measurement does not add information beyond that obtained by measuring LDL concentration, triglyceride levels and HDL concentrations. Therefore, it remains debatable whether to measure LDL particle size in cardiovascular risk assessment and, if so, in which categories of patient. Therapeutic modulation of LDL particle size or number appears beneficial in reducing the risk of cardiovascular events, but no clear causal relationship has been shown, because of confounding factors, including lipid and non-lipid variables. Studies are needed to investigate the clinical significance of LDL size measurements in patients with coronary and non-coronary forms of atherosclerosis; in particular, to test whether LDL size is associated with even higher vascular risk, and whether LDL size modification may contribute to secondary prevention in such patients.

Fibrates in combination with statins in the management of dyslipidemia

While elevated low-density lipoprotein cholesterol is the primary target of hypercholesterolemia treatment, high triglycerides and low high-density lipoprotein cholesterol are also important targets for therapy. Correcting these lipid abnormalities should be an integral part of therapy in hypertensive individuals. Medications such as the fibrates are effective and well tolerated for reducing triglycerides and increasing high-density lipoprotein cholesterol, and their use has resulted in a reduction in cardiovascular events. Fibrates are also recommended as adjunct therapy for patients receiving statins whose low-density lipoprotein cholesterol or non-high-density lipoprotein cholesterol is not reduced to goal levels. The combination of a statin and a fibrate may, however, raise the risk of myopathy and rhabdomyolysis. Gemfibrozil, one of the fibrates, but not fenofibrate, interferes with statin glucuronidation, which may increase the risk of myopathy due to elevations in statin serum levels. This may at least partially explain the lower incidence of myopathy with fenofibrate compared with gemfibrozil when combined with statins. Combination therapy with a fibrate and a statin is a potentially useful therapy for patients with atherogenic lipid profiles, for which fenofibrate appears to be a more appropriate choice due to less myopathic potential.

Management of the Metabolic Syndrome

The metabolic syndrome is most commonly defined as the presence of three or more of the following atherogenic risk factors: increased abdominal waist circumference, hypertriglyceridemia, low serum high-density lipoprotein level, raised blood pressure, and a fasting blood sugar level greater than 110 mg/dL. It is associated with increased risk for the development of atherosclerosis and cardiovascular disease. Current management recommendations promote therapeutic lifestyle changes (mainly diet and exercise) for all of the core elements of the syndrome. Pharmacologic therapy is indicated in most patients with atherogenic dyslipidemia and in some with hyperglycemia and raised blood pressure. These therapeutic measures are able to favorably modify the core components of the metabolic syndrome and it is hoped that they will also improve the long-term cardiovascular prognosis in patients with this disorder.

Beneficial vascular and metabolic effects of peroxisome proliferator-activated receptor-alpha activators

Fibric acid is a synthetic ligand of the nuclear receptor peroxisome proliferator-activated receptor (PPAR)-alpha that is highly expressed in skeletal muscle and heart, where it promotes beta-oxidation of fatty acids to mediate hypolipidemic actions. PPAR-alpha regulates expression of key proteins involved in atherogenesis, vascular inflammation, plaque instability, and thrombosis. Thus, PPAR-alpha may exert direct antiatherogenic actions in the vascular wall. Endothelial dysfunction associated with the metabolic syndrome and other insulin-resistant states is characterized by impaired insulin-stimulated nitric oxide production from the endothelium and decreased blood flow to skeletal muscle. Thus, improvement in insulin sensitivity leads to improved endothelial function. This may be an additional mechanism whereby fibrates decrease the incidence of coronary heart disease. Adiponectin is a protein secreted specifically by adipose cells that may couple regulation of insulin sensitivity with energy metabolism and serve to link obesity with insulin resistance. In this review, we discuss the mechanisms underlying the vascular and metabolic effects of fibrates that may act synergistically to prevent or regress atherosclerosis and coronary heart disease.

Pathophysiology of dyslipidaemia in the metabolic syndrome

The insulin resistance/metabolic syndrome is characterised by the variable coexistence of hyperinsulinaemia, obesity, dyslipidaemia, and hypertension. The pathogenesis of the syndrome has multiple origins, but obesity and sedentary lifestyle coupled with diet and still largely unknown genetic factors clearly interact to produce the syndrome. Dyslipidaemia, the hallmark of the metabolic syndrome, includes increased flux of free fatty acids, raised triglycerides, apolipoprotein B, and small dense low density lipoprotein, and decreased high density lipoprotein cholesterol. The widely prevalent nature of the metabolic syndrome emphasises the importance of its diagnosis and treatment. This review analyses the clinical and dynamic features of this syndrome in the aspect of dyslipidaemia and its management.

The metabolic syndrome: a vascular perspective

The metabolic syndrome (MS) is a clustering of cardiovascular risk factors. Current definitions of MS use hypertension, waist circumference, fasting glucose, triglyceride and HDL-cholesterol levels as defining variables. The prevalence of MS is increasing in our society due to lifestyle changes that result in decreased physical activity and increased body weight. Patients with MS have a three times greater risk of coronary heart disease and stroke, and a two to four times greater risk of dying from atherosclerotic coronary heart disease than those without MS. Imaging studies have shown an increased burden and progression of atherosclerosis. Also, MS patients seem to be more vulnerable to events at comparable levels of atherosclerosis. First-line treatment for MS is therapeutic lifestyle intervention, including exercise and weight reduction. Medical intervention strategies using blood pressure-lowering medication, statins, fibrates and metformin seem the most appropriate to date. The effects of thiazolidinediones on cardiovascular endpoints have not been studied to a large extent in the setting of MS. Evidence regarding risk assessment and optimal medical strategies will be an important aspect of vascular research in the coming years.

Responsiveness of plasma lipids and lipoproteins to plant stanol esters

Plant stanols have been shown to reduce serum levels of low-density lipoprotein (LDL) cholesterol, and they are an attractive adjunct in dietary therapy for elevated LDL cholesterol. This investigation addressed 3 questions through metabolic studies in human subjects: (1) whether plant stanol esters given at higher doses than the 2-g/day dose recommended by the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) will provide additional LDL-lowering efficacy (study 1); (2) whether substantial reduction in LDL cholesterol can be obtained in postmenopausal women with hypercholesterolemia by addition of plant stanol esters to the diet (study 2); and (3) whether ATP III goals can be obtained by adding plant stanol esters to an LDL-lowering regimen in high-risk patients who retain LDL cholesterol levels in the above-optimal range (ie, 2.6 to 3.3 mmol/L [100 to 129 mg/dL]), despite ongoing statin therapy (study 3). Study 1 showed that maximal LDL lowering with plant stanols in the form of esters can be achieved at a dose of 2 g/day. Higher doses do not provide additional efficacy. Study 2 demonstrated that stanol esters can reduce LDL cholesterol levels in postmenopausal women by about 13%, which makes use of stanol esters attractive as a component of nondrug therapy in these women who generally are at relatively low risk for coronary heart disease. Finally, study 3 found that plant stanols provide additional lowering of LDL cholesterol when added to ongoing statin therapy. This makes plant stanols an attractive dietary component to help to achieve the goals of LDL-lowering therapy in patients requiring an LDL-lowering drug.

Additive beneficial effects of fenofibrate combined with atorvastatin in the treatment of combined hyperlipidemia

OBJECTIVES

We compared vascular and metabolic responses (and adverse responses) to statin and fibrate therapies alone or in combination in patients with combined hyperlipidemia.

BACKGROUND

The mechanisms of action for statins and fibrates are distinct.

METHODS

Fifty-six patients were given atorvastatin 10 mg and placebo, atorvastatin 10 mg and fenofibrate 200 mg, or fenofibrate 200 mg and placebo daily during each two-month treatment period of a randomized, double-blind, placebo-controlled crossover trial with two washout periods of two months' each.

RESULTS

Lipoproteins were changed to a greater extent with combined therapy when compared with atorvastatin or fenofibrate alone. Flow-mediated dilator response to hyperemia and plasma high-sensitivity C-reactive protein and fibrinogen levels were changed to a greater extent with combined therapy when compared with atorvastatin or fenofibrate alone (p < 0.001, p = 0.182, and p = 0.015 by analysis of variance [ANOVA], respectively). The effects of combined therapy or fenofibrate alone on plasma adiponectin levels and insulin sensitivity (determined by the Quantitative Insulin-Sensitivity Check Index [QUICKI]) were significantly greater than those of atorvastatin alone (p = 0.022 for adiponectin and p = 0.049 for QUICKI by ANOVA). No patients were withdrawn from the study as the result of serious adverse effects.

CONCLUSIONS

Combination therapy is safe and has beneficial additive effects on endothelial function in patients with combined hyperlipidemia.

Influence of extended-release nicotinic acid on nonesterified fatty acid flux in the metabolic syndrome with atherogenic dyslipidemia

Nicotinic acid has favorable effects on atherogenic dyslipidemia. However, in some patients who have diabetes, crystalline nicotinic acid decreases glycemic control; this effect could be due to a marked rebound of nonesterified fatty acids (NEFAs) observed after nicotinic acid suppression of lipolysis in adipose tissue. Recent reports have indicated that small doses of extended-release nicotinic acid do not cause a substantial decrease in glucose levels. Therefore, in this study, we examined whether 2 g/day of extended-release nicotinic acid abolishes the NEFA rebound that is reported with crystalline nicotinic acid. Seventeen men who had the metabolic syndrome (8 did not have type 2 diabetes and 9 did) were treated for 4 months. At baseline and at 4 months, measurements were made of plasma glucose, insulin, and NEFA during an oral glucose tolerance test. At 3 months, effects of extended-release nicotinic acid on NEFA levels and flux rates were determined on 3 separate days at 3 separate intervals after the final dose of nicotinic acid (4, 9, and 28 hours). Values obtained at 28 hours were taken as baseline (i.e., no nicotinic acid remaining in the circulation). After 4 hours (percent baseline), NEFA levels were -30% without diabetes and -37% with diabetes, and flux rates were -21% without diabetes and -25% with diabetes; after 9 hours, NEFA levels were 43% without diabetes and 50% with diabetes, and flux rates were 38% without diabetes and 70% with diabetes. Extended-release nicotinic acid did not abolish NEFA rebound. Nonetheless, the rebound was much less than previously reported for crystalline nicotinic acid. Moreover, after 4 months of nicotinic acid therapy, levels of NEFA, glucose, and insulin during the oral glucose tolerance test were not significantly different from those before institution of nicotinic acid therapy, suggesting minimal changes in insulin sensitivity.

Combination of dietary phytosterols plus niacin or fenofibrate: effects on lipid profile and atherosclerosis in apo E-KO mice

Patients with mixed dyslipidemias (increased LDL cholesterol and triglyceride as well as low HDL cholesterol levels) benefit from a combination of lipid-modifying drugs such as statins, niacin, fibrates and ezetemibe. However, safety, tolerability and cost are a concern in drug combination therapy. Dietary phytosterols reduce LDL cholesterol, and niacin or fenofibrate primarily reduces triglyceride and increases HDL-cholesterol levels. Thus, we hypothesized that a combination of phytosterols with niacin or fenofibrate will synergistically impact lipoprotein profile and atherogenesis in apo E-KO mice. Phytosterols alone significantly reduced plasma total cholesterol levels (14.1 vs. 16.9 mmol/L, P < .05) and the extent of atherosclerosis (0.42 vs. 0.15 mm(2), P < .05). The addition of fenofibrate to phytosterols increased plasma total cholesterol levels by >50% (14.1 vs. 21.6 mmol/L, P < .05) and decreased HDL-cholesterol concentrations by 50% (0.8 vs. 0.4 mmol/L). These changes were accompanied by slight reductions in the extent of atherosclerosis (0.42 vs. 0.34 mm(2), P > 0.05) as compared to controls, suggesting other potential anti-atherogenic effects of fenofibrate. Unlike fenofibrate, niacin caused an increase of 150% (P < .05) in HDL-cholesterol concentrations and a decrease of 22% (P < .05) in total cholesterol levels which were associated with significant reductions (65%, P < .05) in atherosclerotic lesion size as compared to controls. Neither the addition of niacin nor of fenofibrate reduced plasma triglyceride levels. In conclusion, the addition of niacin to phytosterols synergistically increases HDL-cholesterol levels, while a combination of phytosterols and fenofibrate results in no synergistic effects in apo E-KO mice. Further studies in other animal models are needed to establish synergetic effects between these lipid-modifying dietary and pharmacological agents.

Efficacy and safety of the coadministration of ezetimibe with fenofibrate in patients with mixed hyperlipidaemia

AIMS

To examine the efficacy and safety of coadministered ezetimibe (EZE) with fenofibrate (FENO) in patients with mixed hyperlipidaemia.

METHODS AND RESULTS

This was a multicentre, randomized, double-blind, placebo-controlled, parallel arm trial in patients with mixed hyperlipidaemia [LDL-cholesterol (LDL-C), 3.4-5.7 mmol/L (2.6-4.7 mmol/L for patients with type 2 diabetes); triglycerides (TG), 2.3-5.7 mmol/L] and no history of coronary heart disease (CHD), CHD-equivalent disease (except for type 2 diabetes), or CHD risk score>20%. A total of 625 patients was randomized in a 1:3:3:3 ratio to one of four daily treatments for 12 weeks: placebo; EZE 10 mg; FENO 160 mg; FENO 160 mg plus EZE 10 mg (FENO+EZE). The primary endpoint compared the LDL-C lowering efficacy of FENO+EZE vs. FENO alone. LDL-C, non-HDL-cholesterol (non-HDL-C), and apolipoprotein B were significantly (P<0.001) reduced with FENO+EZE when compared with FENO or EZE alone. TG levels were significantly decreased and HDL-C was significantly increased with FENO+EZE and FENO treatments when compared with placebo (P<0.001). Coadministration therapy reduced LDL-C by 20.4%, non-HDL-C by 30.4%, TG by 44.0%, and increased HDL-C by 19.0%. At baseline, >70% of all patients exhibited the small, dense LDL pattern B profile. A greater proportion of patients on FENO+EZE and FENO alone treatments shifted from a more atherogenic LDL size pattern to a larger, more buoyant, and less atherogenic LDL size pattern at study endpoint than those on placebo or EZE. All three active therapies were well tolerated.

CONCLUSION

Coadministration of EZE with FENO provided a complementary efficacy therapy that improves the atherogenic lipid profile of patients with mixed hyperlipidaemia.

Management of diabetic dyslipidemia

Identification and management of dyslipidemia is an important element in the multi-factorial approach to prevent coronary heart disease. Diabetic dyslipidemia typically consists of elevated triglyceride, low high-density lipoprotein cholesterol, predominance of small, dense low-density lipoprotein (LDL) particles, and average LDL cholesterol (LDL-C). Lipid-lowering therapy has a beneficial effect on cardiovascular outcomes. Statin treatment is beneficial in patients who are older than 40 years of age, irrespective of the LDL-C value. To achieve lipid targets, attention should be directed first toward nonpharmacologic therapeutic interventions, such as diet, exercise, smoking cessation, weight loss, and improving glycemic control. Although statin therapy is recommended for most subjects, judicious use of combination therapy should be considered in the highest risk subjects.

Effectiveness and tolerability of simvastatin plus fenofibrate for combined hyperlipidemia (the SAFARI trial)

Patients with combined hyperlipidemia (elevated triglyceride [TG] levels, elevated low-density lipoprotein [LDL] cholesterol, and multiple lipoprotein abnormalities) are at increased risk for coronary heart disease. We conducted a multicenter (in the United States), randomized, double-blind, active-controlled, 18-week study to determine if combination therapy with simvastatin plus fenofibrate is more effective in reducing elevated TG levels, thus improving the lipoprotein pattern in patients with combined hyperlipidemia compared with simvastatin monotherapy, and to evaluate safety and tolerability. Patients (aged 21 to 68 years) with a diagnosis of combined hyperlipidemia (fasting TG levels >/=150 and </=500 mg/dl, and LDL cholesterol >130 mg/dl) received simvastatin monotherapy (20 mg/day, n = 207) or simvastatin 20 mg plus fenofibrate (160 mg/day) combination therapy (n = 411) for 12 weeks following a 6-week diet and placebo run-in period. From baseline to week 12, median TG levels decreased 43.0% (combination therapy) and 20.1% (simvastatin monotherapy [treatment difference -23.6%, p <0.001]). Mean LDL cholesterol levels decreased 31.2% and 25.8% (treatment difference -5.4%, p <0.001), and high-density lipoprotein cholesterol levels increased 18.6% and 9.7% (treatment difference 8.8%, p <0.001) in the combination therapy versus monotherapy groups, respectively. No drug-related serious adverse experiences were observed. No patient experienced clinical myopathy or severe abnormalities in liver function. Combination therapy with simvastatin 20 mg and fenofibrate 160 mg in patients with combined hyperlipidemia resulted in additional improvement in all lipoprotein parameters measured compared with simvastatin 20 mg monotherapy and was well tolerated. Thus, this combination therapy is a beneficial therapeutic option for managing combined hyperlipidemia.

Prevention and treatment of the metabolic syndrome

The prevalence of the metabolic syndrome is increasing owing to lifestyle changes leading to obesity. This syndrome is a complex association of several interrelated abnormalities that increase the risk for cardiovascular disease and progression to diabetes mellitus (DM). Insulin resistance is the key factor for the clustering of risk factors characterizing the metabolic syndrome. The National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III defined the criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. According to these guidelines, treatment involves the improvement of the underlying insulin resistance through lifestyle modification (eg, weight reduction and increased physical activity) and possibly by drugs. The coexistent risk factors (mainly dyslipidemia and hypertension) should also be addressed. Since the main goal of lipid-lowering treatment is to achieve the NCEP low-density lipoprotein cholesterol (LDL-C) target, statins are a good option. However, fibrates (as monotherapy or in combination with statins) are useful for the treatment of the metabolic syndrome that is commonly associated with hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) levels. The blood pressure target is < 140/90 mm Hg. The effect on carbohydrate homeostasis should possibly be taken into account in selecting an antihypertensive drug. Patients with the metabolic syndrome commonly have other less well-defined metabolic abnormalities (eg, hyperuricemia and raised C-reactive protein levels) that may also be associated with an increased cardiovascular risk. It seems appropriate to manage these abnormalities. Drugs that beneficially affect carbohydrate metabolism and delay or even prevent the onset of DM (eg, thiazolidinediones or acarbose) could be useful in patients with the metabolic syndrome. Furthermore, among the more speculative benefits of treatment are improved liver function in nonalcoholic fatty liver disease and a reduction in the risk of acute gout.

Managing cardiovascular risk inpatients with metabolic syndrome

The metabolic syndrome is a constellation of risk factors that contribute to the onset of type 2 diabetes mellitus and cardiovascular disease (CVD). CVD has been identified by the National Cholesterol Education Program (NCEP) as the primary clinical outcome of the metabolic syndrome. Although no algorithm is currently available for estimating the absolute risk of CVD for patients with the metabolic syndrome, screening for cardiovascular (CV) risk in these patients involves testing for lipoprotein abnormalities (namely, an analysis of specific low-density lipoprotein particle numbers) and an assessment of various surrogate markers for subclinical coronary artery disease. Such screening can be used to help predict the development of CVD and thereby allow for effective interventions to help prevent coronary events. Strategies for reducing CV risk in patients with the metabolic syndrome are multifactorial. In addition to placing an emphasis on therapeutic lifestyle changes that increase levels of physical activity, dietary modification, and weight reduction, several pharmacologic therapies are available. One novel approach for managing CV risk in patients with the metabolic syndrome involves the inhibition of the endocannabinoid system, including the use of rimonabant. A review of CV risk factors in patients with the metabolic syndrome is beneficial for clinicians to apply in the care of their patients, along with a discussion about strategies for identifying at-risk patients and managing CVD risk for these patients.

Metabolic syndrome: therapeutic considerations

The metabolic syndrome is a constellation of metabolic risk factors for atherosclerotic cardiovascular disease (ASCVD) occurring in one individual. There are five cardiovascular risk factors that accompany the metabolic syndrome: atherogenic dyslipidemia [elevated apolipoprotein B (apo B), elevated triglyceride, small low-density lipoprotein (LDL) particles, and low high-density lipoprotein (HDL)cholesterol], elevated blood pressure, elevated glucose, a prothrombotic state, and a proinflammatory state. The likelihood of an individual developing metabolic syndrome is enhance by underlying risk factors, notably, obesity, insulin resistance, lack of physical activity, advancing age, and hormonal factors (e.g., androgens and corticosteroids). Besides being at higher risk for ASCVD, persons with the metabolic syndrome are at increased risk for type 2 diabetes. Persons with the metabolic syndrome deserve management in the clinical setting to reduce the risk for both ASCVD and type 2 diabetes. The two major therapeutic strategies for treatment of affected persons are modification of the underlying risk factors and separate drug treatment of the particular metabolic risk factors when appropriate. First-line therapy for underlying risk factors is therapeutic lifestyle changes, i.e., weight loss in obese persons, increased physical activity, and anti-atherogenic diet. These changes will improve all of the metabolic risk factors. Whether use of drugs to reduce insulin resistance is effective, safe, and cost-effective before the onset of diabetes awaits the results of more clinical research. Turning to individual risk components, for atherogenic dyslipidemia, drug therapies that promote lowering of apo B and raise HDL cholesterol will be needed for higher risk patients. Treatment of categorical hypertension with drugs has become standard practice. When hyperglycemia reaches the diabetic level, glucose-lowering agents will become necessary when dietary control is no longer effective, and reduction of a prothrombotic state with low-dose aspirin may be indicated in higher-risk patients.

Management of diabetic dyslipidemia: need for reappraisal of the goals

Cardiovascular disease is the leading cause of mortality among people with diabetes mellitus, accounting for 70% of all deaths. As the prevalence of diabetes increases significantly worldwide, greater attention must be focused on preventing cardiovascular events in this group. One contributor to this increased event rate is the characteristic pattern of dyslipidemia in diabetic patients, consisting of elevated serum triglyceride levels, decreased high-density lipoprotein levels, and an increased proportion of small, dense, low-density lipoproteins. Several pharmacologic agents have been used to treat this dyslipidemia including HMG-CoA reductase inhibitors, fibric acid derivatives, niacin (nicotinic acid), thiazolidinediones, and fish oils, as well as other non-pharmacologic measures. Currently, the most extensive data for a reduction in cardiovascular events in patients with diabetes exist for HMG-CoA reductase inhibitors. The results of these trials indicate that HMG-CoA reductase inhibitor therapy should be considered for all patients with diabetes at sufficient risk for cardiovascular events, regardless of serum low-density lipoprotein-cholesterol level. Several ongoing trials of various pharmacologic agents should help clarify the role of these agents alone and in combination with HMG-CoA reductase inhibitors in the management of diabetic dyslipidemia.

Fibrates

Atherosclerosis of the large arteries is the main origin of cerebro- and cardiovascular diseases, the leading causes of mortality and morbidity in industrialized countries. The pathophysiology of coronary and cerebrovascular atherosclerosis is multifactorial and complex. Fibrates are hypolipidemic drugs that lower progression of atherosclerotic lesions mainly through activation of the nuclear receptor peroxisome-proliferator activated receptor-alpha. In addition, fibrates exert pleiotropic and anti-inflammatory actions. In this chapter, we will focus on the different effects of fibrates impacting on the development of atherosclerosis.

Addressing cardiovascular risk beyond low-density lipoprotein cholesterol: the high-density lipoprotein cholesterol story

A large body of evidence from numerous, well-controlled, randomized trials demonstrates that treatment with statins reduce morbidity and mortality from cardiovascular disease (CVD). Although these observations are important and have resulted in the adoption of standard of care approaches to the management of CVD risk, they do not tell the whole story. When reviewing these landmark trials it is clear that on average two thirds of events are not prevented. This leads to the evaluation of risk beyond low-density lipoprotein cholesterol. This review focuses on the association of low high-density lipoprotein (HDL) cholesterol and increased CVD risk, the published trials that study the effect of raising HDL cholesterol on CVD outcomes, and the novel approaches toward HDL cholesterol raising that are on the horizon.