A randomized trial of the effects of atorvastatin and niacin in patients with combined hyperlipidemia or isolated hypertriglyceridemia. Collaborative Atorvastatin Study Group

Efficacy of Nutraceutical Combination of Monacolin K, Berberine, and Silymarin on Lipid Profile and PCSK9 Plasma Level in a Cohort of Hypercholesterolemic Patients

The guidelines for the treatment of dyslipidemias include the use of nutraceuticals (NUTs) in association with lifestyle modifications to achieve therapeutic goals. In NUT pill, different substances may be associated; in this study we investigated a combined NUT containing monacolin K (MonK)+KA (1:1), berberine (BBR), and silymarin. The aim of the study was to evaluate low-density lipoprotein cholesterol (LDL-C) reduction in 53 patients suffering from polygenic hypercholesterolemia, characterized by a low/intermediate cardiovascular risk calculated with SCORE algorithm. The effects on lipid profile of 2-month treatment with NUT containing MonK+KA (1:1), BBR, and sylimarin, were compared with Atorvastatin (ATO) 10 mg administrated in a matched control group. Serum proprotein convertase subtilisin/kexin type 9 (PCSK9) levels and the cholesterol loading capacity (CLC) were determined at baseline and at the end of the study in NUT-treated group; variations were assessed. NUT was effective as lipid-lowering agent with a wide interindividual response variability (mean LDL-C from 170.8 ± 19.9 to 123.8 ± 20.0 with a change of -47.0 ± 21.5 mg/dL; P < .001) and the effect was similar to that induced by ATO. The use of NUT significantly modified PCSK9 levels (P < .01) and CLC (P < .001), ultimately suppressing the serum-mediated foam cell generation directly measured on human macrophages. NUT reduces LDL-C levels with an effect similar to what is induced by 10 mg of ATO and ex vivo improves the functional profile of lipoproteins with antiatherogenic action.

Niacin Alternatives for Dyslipidemia: Fool's Gold or Gold Mine? Part I: Alternative Niacin Regimens

Niacin was the first drug demonstrating lowered cholesterol prevents coronary heart disease (CHD) events, with two clinical CHD outcome studies establishing a cardioprotective niacin regimen: 1 g thrice daily with meals. Though cardioprotective, skin toxicity limits niacin's use, fostering several variations to improve tolerability. One of these, an extended-release (ER) alternative, proved immensely successful commercially, dominating clinical practice despite departing from the established regimen in several critical ways. Hence, improved tolerability may have come at the cost of diminished efficacy, posing a conundrum: Does it still help the population at risk for CHD to broaden a drug's acceptance by "watering it down"? This question is crucial at this stage now that the ER alternative failed to recapitulate the benefits of the established cardioprotective niacin regimen in two trials of the alternative approach: AIM-HIGH and HPS2-THRIVE. Part I of this review discusses how vastly the ER alternative departs from the established cardioprotective regimen, why that is important physiologically, and how it may explain the findings of AIM-HIGH and HPS2-THRIVE. Given important gaps left by statin therapy, the established cardioprotective niacin regimen remains an important evidence-based therapy for the statin intolerant or statin averse.

Lipid-lowering efficacy of atorvastatin

BACKGROUND

This represents the first update of this review, which was published in 2012. Atorvastatin is one of the most widely prescribed drugs and the most widely prescribed statin in the world. It is therefore important to know the dose-related magnitude of effect of atorvastatin on blood lipids.

OBJECTIVES

Primary objective To quantify the effects of various doses of atorvastatin on serum total cholesterol, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol and triglycerides in individuals with and without evidence of cardiovascular disease. The primary focus of this review was determination of the mean per cent change from baseline of LDL-cholesterol. Secondary objectives • To quantify the variability of effects of various doses of atorvastatin.• To quantify withdrawals due to adverse effects (WDAEs) in placebo-controlled randomised controlled trials (RCTs).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 11, 2013), MEDLINE (1966 to December Week 2 2013), EMBASE (1980 to December Week 2 2013), Web of Science (1899 to December Week 2 2013) and BIOSIS Previews (1969 to December Week 2 2013). We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled and uncontrolled before-and-after trials evaluating the dose response of different fixed doses of atorvastatin on blood lipids over a duration of three to 12 weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility criteria for studies to be included and extracted data. We collected information on withdrawals due to adverse effects from placebo-controlled trials.

MAIN RESULTS

In this update, we found an additional 42 trials and added them to the original 254 studies. The update consists of 296 trials that evaluated dose-related efficacy of atorvastatin in 38,817 participants. Included are 242 before-and-after trials and 54 placebo-controlled RCTs. Log dose-response data from both trial designs revealed linear dose-related effects on blood total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides. The Summary of findings table 1 documents the effect of atorvastatin on LDL-cholesterol over the dose range of 10 to 80 mg/d, which is the range for which this systematic review acquired the greatest quantity of data. Over this range, blood LDL-cholesterol is decreased by 37.1% to 51.7% (Summary of findings table 1). The slope of dose-related effects on cholesterol and LDL-cholesterol was similar for atorvastatin and rosuvastatin, but rosuvastatin is about three-fold more potent. Subgroup analyses suggested that the atorvastatin effect was greater in females than in males and was greater in non-familial than in familial hypercholesterolaemia. Risk of bias for the outcome of withdrawals due to adverse effects (WDAEs) was high, but the mostly unclear risk of bias was judged unlikely to affect lipid measurements. Withdrawals due to adverse effects were not statistically significantly different between atorvastatin and placebo groups in these short-term trials (risk ratio 0.98, 95% confidence interval 0.68 to 1.40).

AUTHORS' CONCLUSIONS

This update resulted in no change to the main conclusions of the review but significantly increases the strength of the evidence. Studies show that atorvastatin decreases blood total cholesterol and LDL-cholesterol in a linear dose-related manner over the commonly prescribed dose range. New findings include that atorvastatin is more than three-fold less potent than rosuvastatin, and that the cholesterol-lowering effects of atorvastatin are greater in females than in males and greater in non-familial than in familial hypercholesterolaemia. This review update does not provide a good estimate of the incidence of harms associated with atorvastatin because included trials were of short duration and adverse effects were not reported in 37% of placebo-controlled trials.

Systematic review: Evaluating the effect of lipid-lowering therapy on lipoprotein and lipid values

PURPOSE

This systematic review was performed to summarize published experience using low density lipoprotein particle number (LDL-P) to monitor the efficacy of lipid-lowering pharmacotherapies.

METHODS

Studies were identified from a literature search of MEDLINE (January 1, 2000 - June 30, 2012); and abstract searches of select conferences. All accepted studies reported mean (or median) nuclear magnetic resonance (NMR)-based LDL-P values for at least 10 subjects receiving lipid lowering pharmacotherapy.

RESULTS

Searches revealed 36 studies (with 61 treatment arms) in which LDL-P measurements were reported pre- and post-treatment. Most studies also reported changes in low-density lipoprotein cholesterol (LDL-C), but fewer studies reported changes in apolipoprotein B (apoB)(n = 20) and non-HDL-C (n = 28). Treatments included statins (22 arms/15 studies), fibrates (7 arms/7 studies), niacin (7 arms/6 studies), bile acid sequestrants (5 arms/2 studies), an anti-apoB oligonucleotide (2 arms/2 studies), combination therapies (8 arms/6 studies), anti-diabetics (5 arms/4 studies), and, other treatments (5 arms/2 studies). Lipid-lowering pharmacotherapy resulted in reductions in mean LDL-P in all but two studies. In several statin studies, the percent reductions in LDL-P were smaller than reductions in LDL-C, comparable changes were reported when LDL-P and apoB, were reported.

CONCLUSIONS

Study-level data from this systemic review establish that different lipid lowering agents can lead to discordance between LDL-P and LDL-C, therefore, basing LDL-lowering therapy only on the achievement of cholesterol goals may result in a treatment gap. Therefore, the use of LDL-P for monitoring lipid-lowering therapy, particularly for statins, can provide a more accurate assessment of residual cardiovascular risk.

Lipid lowering efficacy of atorvastatin

BACKGROUND

Atorvastatin is one of the most widely prescribed drugs and the most widely prescribed statin in the world. It is therefore important to know the dose-related magnitude of effect of atorvastatin on blood lipids.

OBJECTIVES

To quantify the dose-related effects of atorvastatin on blood lipids and withdrawals due to adverse effects (WDAE).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library Issue 4, 2011, MEDLINE (1966 to November 2011), EMBASE (1980 to November 2011), ISI Web of Science (1899 to November 2011) and BIOSIS Previews (1969 to November 2011). No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled and uncontrolled before-and-after trials evaluating the dose response of different fixed doses of atorvastatin on blood lipids over a duration of 3 to 12 weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. WDAE information was collected from the placebo-controlled trials.

MAIN RESULTS

Two hundred fifty-four trials evaluated the dose-related efficacy of atorvastatin in 33,505 participants. Log dose-response data revealed linear dose-related effects on blood total cholesterol, low-density lipoprotein (LDL)-cholesterol and triglycerides. Combining all the trials using the generic inverse variance fixed-effect model for doses of 10 to 80 mg/day resulted in decreases of 36% to 53% for LDL-cholesterol. There was no significant dose-related effects of atorvastatin on blood high-density lipoprotein (HDL)-cholesterol. WDAE were not statistically different between atorvastatin and placebo for these short-term trials (risk ratio 0.99; 95% confidence interval 0.68 to 1.45).

AUTHORS' CONCLUSIONS

Blood total cholesterol, LDL-cholesterol and triglyceride lowering effect of atorvastatin was dependent on dose. Log dose-response data was linear over the commonly prescribed dose range. Manufacturer-recommended atorvastatin doses of 10 to 80 mg/day resulted in 36% to 53% decreases of LDL-cholesterol. The review did not provide a good estimate of the incidence of harms associated with atorvastatin because of the short duration of the trials and the lack of reporting of adverse effects in 37% of the placebo-controlled trials.

Stability Indicating RP-HPLC Estimation of Atorvastatin Calcium and Amlodipine Besylate in Pharmaceutical Formulations

A simple, specific, accurate and stability indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of atorvastatin calcium and amlodipine besylate in tablet dosage forms. A phenomenex Gemini C-18, 5 μm column having 250×4.6 mm i.d. in isocratic mode, with mobile phase containing 0.02 M potassium dihydrogen phosphate:acetonitrile:methanol (30:10:60, v/v/v) adjusted to pH 4 using ortho phosphoric acid was used. The flow rate was 1.0 ml/min and effluents were monitored at 240 nm. The retention times of atorvastatin calcium and amlodipine besylate were 11.6 min and 4.5 min, respectively. The calibration curves were linear in the concentration range of 0.08-20 μg/ml for atorvastatin calcium and 0.1-20 μg/ml for amlodipine besylate. Atorvastatin calcium and amlodipine besylate stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. The proposed method was validated and successfully applied to the estimation of atorvastatin calcium and amlodipine besylate in combined tablet dosage forms.

What combination therapy with a statin, if any, would you recommend?

The latest recommended goals for blood lipid levels may require multiple lipid drugs. Lower doses in combination may render more efficacy and safety than highest doses of single agents. Except for isolated hypoalphalipoproteinemia (a low level of high-density lipoprotein cholesterol), therapies will start with a statin. All marketed statins are acceptable. The choice may be based on dose- efficacy and patient's tolerability. High-potency statins (eg, atorvastatin, simvastatin, or rosuvastatin) are often chosen. Currently, generic statins, such as simvastatin, lovastatin, pravastatin, and fluvastatin, offer cost benefits. The choice of added agent depends on the "residual lipoprotein abnormalities" after statin therapy, efficacy, compliance issues, and cost. Approved "combined" preparations improve cost and compliance. To further lower low-density lipoprotein cholesterol, ezetimibe is a safe, efficacious choice, pending resolution of a controversial trial's results. Colesevelam is moderately effective and the best tolerated bile acids sequestrant. In combined dyslipidemias, extended-release niacin is the best tolerated niacin preparation; other quality-controlled immediate-release preparations have similar safety and efficacy but produce more flushing of the skin. Niacin or fenofibrate is effective in normalizing high-density lipoprotein and triglyceride levels persisting after statin therapy. Agents approved by the US Food and Drug Administration and the latest guidelines of the National Cholesterol Education Program, American Heart Association/American College of Cardiology provide choices and indications of drug combinations.

The role of high-density lipoproteins in reducing the risk of vascular diseases, neurogenerative disorders, and cancer

High-density lipoprotein (HDL) is one of the major carriers of cholesterol in the blood. It attracts particular attention because, in contrast with other lipoproteins, as many physiological functions of HDL influence the cardiovascular system in favourable ways unless HDL is modified pathologically. The functions of HDL that have recently attracted attention include anti-inflammatory and anti-oxidant activities. High anti-oxidant and anti-inflammatory activities of HDL are associated with protection from cardiovascular disease. Atheroprotective activities, as well as a functional deficiency of HDL, ultimately depend on the protein and lipid composition of HDL. Further, numerous epidemiological studies have shown a protective association between HDL-cholesterol and cognitive impairment. Oxidative stress, including lipid peroxidation, has been shown to be the mediator of the pathologic effects of numerous risk factors of Alzheimer's disease. Lifestyle interventions proven to increase HDL- cholesterol levels including "healthy" diet, regular exercise, weight control, and smoking cessation have also been shown to provide neuro-protective effects. This review will focus on current knowledge of the beneficial effects of HDL-cholesterol as it relates to cardiovascular diseases, breast and lung cancers, non-Hodgkin's lymphoma, as well as its neuroprotective potential in reducing the risk of Alzheimer's disease and dementia.

A "hot" topic in dyslipidemia management--"how to beat a flush": optimizing niacin tolerability to promote long-term treatment adherence and coronary disease prevention

Niacin is the most effective lipid-modifying agent for raising high-density lipoprotein cholesterol levels, but it also causes cutaneous vasodilation with flushing. To determine the frequency of flushing in clinical trials, as well as to delineate counseling and treatment approaches to prevent or manage flushing, a MEDLINE search was conducted of English-language literature from January 1, 1985, through April 7, 2009. This search used the title keywords niacin or nicotinic acid crossed with the Medical Subject Headings adverse effects and human. Niacin flushing is a receptor-mediated, mainly prostaglandin D(2)-driven phenomenon, the frequency, onset, and duration of which are largely determined by the distinct pharmacological and metabolic profiles of different niacin formulations. Subjective assessments include ratings of redness, warmth, itching, and tingling. In clinical trials, most (>60%) niacin users experienced mild or moderate flushing, which tended to decrease in frequency and severity with continued niacin treatment, even with advancing doses. Approximately 5% to 20% of patients discontinued treatment because of flushing. Flushing may be minimized by taking niacin with meals (or at bedtime with a low-fat snack), avoiding exacerbating factors (alcohol or hot beverages), and taking 325 mg of aspirin 30 minutes before niacin dosing. The current review advocates an initially slow niacin dose escalation from 0.5 to 1.0 g/d during 8 weeks and then from 1.0 to 2.0 g in a single titration step (if tolerated). Through effective counseling, treatment prophylaxis with aspirin, and careful dose escalation, adherence to niacin treatment can be improved significantly. Wider implementation of these measures should enable higher proportions of patients to reach sufficient niacin doses over time to prevent cardiovascular events.

Niacin and fibrates in atherogenic dyslipidemia: pharmacotherapy to reduce cardiovascular risk

Although statin therapy represents a cornerstone of cardiovascular disease (CVD) prevention, a major residual CVD risk (60-70% of total relative risk) remains, attributable to both modifiable and non-modifiable risk factors. Among the former, low levels of HDL-C together with elevated triglyceride (TG)-rich lipoproteins and their remnants represent major therapeutic targets. The current pandemic of obesity, metabolic syndrome, and type 2 diabetes is intimately associated with an atherogenic dyslipidemic phenotype featuring low HDL-C combined with elevated TG-rich lipoproteins and small dense LDL. In this context, there is renewed interest in pharmacotherapeutic strategies involving niacin and fibrates in monotherapy and in association with statins. This comprehensive, critical review of available data in dyslipidemic subjects indicates that niacin is more efficacious in raising HDL-C than fibrates, whereas niacin and fibrates reduce TG-rich lipoproteins and LDL comparably. Niacin is distinguished by its unique capacity to effectively lower Lp(a) levels. Several studies have demonstrated anti-atherosclerotic action for both niacin and fibrates. In contrast with statin therapy, the clinical benefit of fibrates appears limited to reduction of nonfatal myocardial infarction, whereas niacin (frequently associated with statins and/or other agents) exerts benefit across a wider range of cardiovascular endpoints in studies involving limited patient numbers. Clearly the future treatment of atherogenic dyslipidemias involving the lipid triad, as exemplified by the occurrence of the mixed dyslipidemic phenotype in metabolic syndrome, type 2 diabetes, renal, and auto-immune diseases, requires integrated pharmacotherapy targeted not only to proatherogenic particles, notably VLDL, IDL, LDL, and Lp(a), but also to atheroprotective HDL.

Current and emerging paradigms in the therapeutic management of atherosclerosis

BACKGROUND

The pathogenesis of atherosclerosis lies in abnormalities in lipoprotein metabolism leading to pathological interactions with vessel walls and the release of inflammatory components, which further aggravate the disease condition.

OBJECTIVE

To elucidate current and emerging trends in drug discovery towards the development of new entities regulating lipoprotein metabolism and inflammatory components to combat the progression of atherosclerosis.

METHODS

Research/review articles in the public domain and press releases were employed.

RESULTS/CONCLUSION

With the recent failure of torcetrapib and succinobucol, drug discovery and development efforts towards the treatment of atherosclerosis have received a big jolt and have been slowed down to a certain extent [corrected]. But this could be a starting point for several new mechanisms that are emerging to discover new drugs to combat the disease.

Pharmacologic management of triglycerides

Currently available cholesterol-lowering pharmacologic agents have been studied for their effect on reducing triglyceride levels. The fibrates increase lipoprotein lipase activity, thereby decreasing the size of triglyceride-rich particles. High doses of niacin can produce decreases in very low-density lipoprotein (VLDL) levels, triglyceride-rich particles, and low-density lipoprotein (LDL) by inhibiting hepatic lipoprotein synthesis. By increasing LDL-receptor activity, the statins increase the removal rate of triglyceride-rich particles. Each class of agents produces various degrees of triglyceride lowering, depending on the existing baseline level and other factors. Patients with elevated LDL who are also hypertriglyceridemic should receive statins as first-line therapy. Niacin may be used as an alternative first-line agent in patients with low LDL elevations. Combination therapy using other agents may be indicated depending on the patient's levels of triglycerides and LDL.

Effects of statins on high-density lipoproteins: a potential contribution to cardiovascular benefit

PURPOSE

The objective was to systematically review clinical trial data on the effects of statins on high-density lipoproteins (HDL) and to examine the possibility that this provides cardiovascular benefits in addition to those derived from reductions in low-density lipoproteins (LDL).

METHODS

The PubMed database was searched for publications describing clinical trials of atorvastatin, pravastatin, rosuvastatin, and simvastatin. On the basis of predefined criteria, 103 were selected for review.

RESULTS

Compared with placebo, statins raise HDL, measured as HDL-cholesterol (HDL-C) and apolipoprotein A-I (apo A-I); these elevations are maintained in the long-term. In hypercholesterolemia, HDL-C is raised by approximately 4% to 10%. The percentage changes are greater in patients with low baseline levels, including those with the common combination of high triglycerides (TG) and low HDL-C. These effects do not appear to be dose-related although there is evidence that, with the exception of atorvastatin, the changes in HDL-C are proportional to reductions in apo B-containing lipoproteins. The most likely explanation is a reduced rate of cholesteryl ester transfer protein (CETP)-mediated flow of cholesterol from HDL. There is some evidence that the statin effects on HDL reduce progression of atherosclerosis and risk of cardiovascular disease independently of reductions in LDL.

CONCLUSION

Statins cause modest increases in HDL-C and apo A-I probably mediated by reductions in CETP activity. It is plausible that such changes independently contribute to the cardiovascular benefits of the statin class but more studies are needed to further explore this possibility.

Atorvastatin monotherapy vs. combination therapy in the management of patients with combined hyperlipidemia

BACKGROUND

Mixed hyperlipidemia is a common disorder characterized by elevated VLDL and LDL levels. Patients with this syndrome usually are in need of combination therapy, comprising a fibric acid derivate with a statin drug in order to achieve LDL and triglyceride target values. Atorvastatin is a hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor demonstrated to be effective in reducing both cholesterol (CHOL) and triglyceride (TG) levels in humans. We examined the efficacy of atorvastatin as monotherapy in achieving a better or the same lipid profile in patients with mixed hyperlipidemia treated with combination therapy.

DESIGN

We compared atorvastatin with a combination of a fibric acid derivate and a statin drug (other than atorvastatin) in a 24-week, prospective randomized, open-label study of 27 patients with mixed hyperlipidemia.

METHODS

All 27 patients had been treated with statin-fibrate therapy in different regimens for at least a year. Atorvastatin at a daily dose of 20 mg was substituted for statin-fibrate therapy. Lipid and safety profiles were assessed.

RESULTS

Atorvastatin significantly reduced total cholesterol, LDL-C, and HDL-C compared to statin-fibrate therapy. In contrast, TG and glucose levels were significantly elevated with atorvastatin. Target LDL-C and TG was achieved in 10 patients with the single therapy of atorvastatin vs. 6 patients under statin-fibrate. In 16 patients, atorvastatin was at least as effective as, or better than, the combination therapy, and was recommended for continuation of treatment.

CONCLUSION

Atorvastatin is an adequate monotherapy for many mixed hyperlipidemia patients. We recommend atorvastatin be considered for every patient suffering from mixed hyperlipidemia.

Effects of niacin on glucose control in patients with dyslipidemia

Niacin (nicotinic acid), the most effective available pharmacotherapy for increasing high-density lipoprotein cholesterol, also lowers triglycerides and hence may be useful, alone or in combination with hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), to offset residual cardiovascular risk in patients with mixed or diabetic dyslipidemia. We conducted a review of published consensus guidelines since 2000 and an English-language PubMed search of prospective, randomized controlled trials and open-label studies from January 1, 1990, through December 31, 2007, concerning the effects of niacin, alone or in combination with statins, on glycemic regulation in dyslipidemic patients (with or without diabetes mellitus). For search terms, we used the title words niacin or nicotinic acid and key words including diabetes, diabetic, dyslipidemia, glucose, glycemic, HbA1c, hemoglobin, hyperglycemia, human, insulin, postprandial, and safety. Retrospective and observational studies, case reports, and case studies were excluded. On the basis of our analysis, the effects of niacin (< or =2.5 g/d), alone or in combination with statins, on fasting glucose (an increase of 4%-5%) and hemoglobin A1c levels (an increase of < or =0.3%) are modest, transient or reversible, and typically amenable to adjustments in oral hypoglycemic regimens without discontinuing niacin. Niacin therapy was infrequently associated with incident diabetes or the need for new insulin prescriptions. Studies showed important clinical benefits of niacin or niacin-statin regimens despite modest effects on glucose control. On a population basis, significant reductions in incidences of cardiovascular events and the degree of atherosclerotic progression associated with long-term niacin (or niacin-statin) therapy in patients with diabetic dyslipidemia outweigh the typically mild effects of this therapy on glycemic regulation. Consensus guidelines recommend monitoring glycemic control after initiating niacin treatment or increasing its dosage.

Suppression of Niacin-induced Vasodilation with an Antagonist to Prostaglandin D2 Receptor Subtype 1

Niacin (nicotinic acid) reduces cardiovascular events in patients with dyslipidemia. However, symptoms associated with niacin-induced vasodilation (e.g., flushing) have limited its use. Laropiprant is a selective antagonist of the prostaglandin D(2) receptor subtype 1 (DP1), which may mediate niacin-induced vasodilation. The aim of this proof-of-concept study was to evaluate the effects of laropiprant (vs placebo) on niacin-induced cutaneous vasodilation. Coadministration of laropiprant 30, 100, and 300 mg with extended-release (ER) niacin significantly lowered flushing symptom scores (by approximately 50% or more) and also significantly reduced malar skin blood flow measured by laser Doppler perfusion imaging. Laropiprant was effective after multiple doses in reducing symptoms of flushing and attenuating the increased malar skin blood flow induced by ER niacin. In conclusion, the DP1 receptor antagonist laropiprant was effective in suppressing both subjective and objective manifestations of niacin-induced vasodilation.

Efficacy and tolerability of combined treatment with L-carnitine and simvastatin in lowering lipoprotein(a) serum levels in patients with type 2 diabetes mellitus

Lipoprotein(a) [Lp(a)] concentration is generally related to coronary artery disease (CAD) and cerebrovascular disease. However, at present, few interventions are available to lower Lp(a) concentrations. We investigated the effects of l-carnitine, co-administered with simvastatin, on hyper-Lp(a) in patients with type 2 diabetes mellitus. We conducted an open, randomised, parallel-group study, in one investigational center (University hospital). Fifty-two patients with type 2 diabetes mellitus, a triglyceride serum levels <400mg/dL (<4.5 mmol/L), and Lp(a) serum levels >20mg/dL (0.71 mmol/L) were randomised to receive simvastatin alone (n=26) or simvastatin plus l-carnitine (n=26) for 60 days. Simvastatin was administered, in both groups, at a dosage of 20 mg/day, while l-carnitine was administered at a dosage of 2g/day once daily. Both treatments were given orally. Serum levels of triglycerides, total cholesterol, LDL cholesterol, high-density lipoprotein (HDL) cholesterol, non-HDL cholesterol (total cholesterol minus HDL cholesterol), apolipoprotein B, and Lp(a) were measured at baseline and 60 days after starting treatment. No difference in time by groups (simvastatin and simvastatin plus l-carnitine) were observed in the reduction of LDL cholesterol, non-HDL cholesterol, and apoB serum levels. On the other hand, Lp(a) serum levels increase from baseline to 60 days in the simvastatin group alone versus a significant decrease in the combination group. Our findings provide support for a possible role of combined treatment with l-carnitine and simvastatin in lowering Lp(a) serum levels in patients with type 2 diabetes mellitus than with simvastatin alone. Our results strongly suggest that l-carnitine may have a role among lipid-lowering strategies.

Statins and fibrates for preventing melanoma

BACKGROUND

Effective treatment for advanced melanoma is lacking. While no drug therapy currently exists for prevention of melanoma, in vitro, case-control, and animal model evidence suggest that lipid-lowering medications, commonly taken for high cholesterol, might prevent melanoma.

OBJECTIVES

To assess the effects of statin or fibrate lipid-lowering medications on melanoma outcomes.

SEARCH STRATEGY

We searched the Cochrane Skin Group Specialised Register (February 2003), CENTRAL (The Cochrane Library Issue 1, 2005), MEDLINE (to March 2003), EMBASE (to September 2003), CANCERLIT (to October 2002), Web of Science (to May 2003), and reference lists of articles. We approached study investigators and pharmaceutical companies for additional information (published or unpublished studies).

SELECTION CRITERIA

Trials involving random allocation of study participants, where experimental groups used statins or fibrates and participants were enrolled for at least four years of therapy.

DATA COLLECTION AND ANALYSIS

Three authors screened 109 abstracts of articles with titles of possible relevance. We then thoroughly examined the full text of 72 potentially relevant articles. We requested unpublished melanoma outcomes data from the corresponding author of each qualifying trial.

MAIN RESULTS

We identified 16 qualifying randomised controlled trials (RCTs) (seven statin, nine fibrate). Thirteen of these trials (involving 62,197 participants) provided data on incident melanomas (six statin, seven fibrate). A total of 66 melanomas were reported in groups receiving the experimental drug and 86 in groups receiving placebo or other control therapies. For statin trials this translated to an odds ratio of 0.90 (95% confidence interval 0.56 to 1.44) and for fibrate trials an odds ratio of 0.58 (95% confidence interval 0.19 to 1.82). Subgroup analyses failed to show statistically significant differences in melanoma outcomes by gender, melanoma occurrence after two years of participation in trial, stage or histology, or trial funding. Subgroup analysis by type of fibrate or statin also failed to show statistically significant differences, except for the statin subgroup analysis which showed reduced melanoma incidence for lovastatin, based on one trial only (odds ratio 0.52, 95% confidence interval 0.27 to 0.99).

AUTHORS' CONCLUSIONS

The melanoma outcomes data collected in this review of RCTs of statins and fibrates does not exclude the possibility that these drugs prevent melanoma. There was a 10% and 42% reduction for participants on statins and fibrates, respectively, however these results were not statistically significant. Until further evidence is established, limiting exposure to ultraviolet radiation remains the most effective way to reduce the risk of melanoma.

Beneficial effects of atorvastatin on sd LDL and LDL phenotype B in statin-naive patients and patients previously treated with simvastatin or pravastatin

BACKGROUND

The presence of increased levels of small dense (sd) LDL (phenotype B) is associated with a substantial increase of cardiovascular disease risk. Since lowering of plasma low-density lipoprotein-cholesterol (LDL-C) by statins involves an up-regulation of the LDL receptor, we questioned whether LDL lowering by atorvastatin affects different LDL subfractions equally.

METHODS

Fifty-four hypercholesterolemic patients, requiring treatment for prevention of coronary heart disease received atorvastatin (10, 20 or 40 mg/day), either as initial therapy (n=33), or as replacement therapy (n=21) for pravastatin or simvastatin (both at 40 mg/day). In addition to plasma lipid measurements, cholesterol LDL subfractions were separated and analysed before and after 3 months of treatment.

RESULTS

In addition to the expected LDL-C decrease (-34%; p<0.0001), a major reduction in sd LDL occurred after atorvastatin therapy (-38.2%; p<0.0001). Interestingly, sd LDL decreased as much in patients previously treated with other statins (-36%; p<0.002). A close correlation (r=0.89, p<0.001) was found between reduction of sd LDL and that of LDL-C, in patients with phenotype B. Although high-density lipoprotein-cholesterol (HDL-C) was not affected by atorvastatin treatment, plasma triglycerides decreased by 27.4% (p<0.0001). Only a weak correlation (r=0.35, p<0.01) was found between the reduction of plasma triglycerides and the decrease of sd LDL after atorvastatin treatment.

CONCLUSION

These results show that the reduction of LDL-C by atorvastatin largely reflects a lowering of sd LDL. Our data also suggest that triglyceride lowering plays only a partial role in sd LDL reduction.

Baseline levels of low-density lipoprotein cholesterol and lipoprotein (a) and the AvaII polymorphism of the low-density lipoprotein receptor gene influence the response of low-density lipoprotein cholesterol to pravastatin treatment

To investigate some individual and genetic factors that may influence the response of low-density lipoprotein cholesterol (LDL-C) to pravastatin treatment, we recruited 440 subjects with hypercholesterolemia (mean age, 57 years; 43% men) from 21 primary health care centers-outpatient clinics into a prospective, multicentered intervention trial. Pravastatin (20 mg/d) was prescribed for 16 weeks. The main outcome was the percentage variation in LDL-C concentration relative to baseline. Blood analyses and genotyping were performed centrally. The results indicated that LDL-C decreased by 20.5% (range, +21% to -66%) after pravastatin treatment. Baseline concentration of LDL-C (the higher the concentration, the greater the decrease), lipoprotein (a) levels (the lower the concentration, the greater the response), and Ava II polymorphism of the LDL-receptor gene significantly influenced the hypolipemic effect ( P < .001, P = .014, and P = .004, respectively). These 3 factors combined explained 10.6% of the variation in LDL-C response. Age, sex, smoking habit, alcohol consumption, body mass index, and apolipoprotein E genotype had no significant effect on response. We conclude that baseline levels of LDL-C and lipoprotein (a) together with the Ava II polymorphism of the LDL-receptor gene have a significant influence on the LDL-C response to pravastatin treatment in patients monitored in a standard primary health care outpatient clinic setting.

Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol (ARBITER) 2: a double-blind, placebo-controlled study of extended-release niacin on atherosclerosis progression in secondary prevention patients treated with statins

BACKGROUND

Niacin reduces coronary heart disease morbidity and mortality when taken either alone or in combination with statins; however, the incremental impact of adding niacin to background statin therapy is unknown.

METHODS AND RESULTS

This was a double-blind randomized placebo-controlled study of once-daily extended-release niacin (1000 mg) added to background statin therapy in 167 patients (mean age 67 years) with known coronary heart disease and low levels of high-density lipoprotein cholesterol (HDL-C; <45 mg/dL). The primary end point was the change in common carotid intima-media thickness (CIMT) after 1 year. Baseline CIMT (0.884+/-0.234 mm), low-density lipoprotein cholesterol (89+/-20 mg/dL), and HDL-C (40+/-7 mg/dL) were comparable in the placebo and niacin groups. Adherence to niacin exceeded 90%, and 149 patients (89.2%) completed the study. HDL-C increased 21% (39 to 47 mg/dL) in the niacin group. After 12 months, mean CIMT increased significantly in the placebo group (0.044+/-0.100 mm; P<0.001) and was unchanged in the niacin group (0.014+/-0.104 mm; P=0.23). Although the overall difference in IMT progression between the niacin and placebo groups was not statistically significant (P=0.08), niacin significantly reduced the rate of IMT progression in subjects without insulin resistance (P=0.026). Clinical cardiovascular events occurred in 3 patients treated with niacin (3.8%) and 7 patients treated with placebo (9.6%; P=0.20).

CONCLUSIONS

The addition of extended-release niacin to statin therapy slowed the progression of atherosclerosis among individuals with known coronary heart disease and moderately low HDL-C.

High-Dose Atorvastatin Reduces Total Plasma Levels of Oxidized Phospholipids and Immune Complexes Present on Apolipoprotein B-100 in Patients With Acute Coronary Syndromes in the MIRACL Trial

BACKGROUND

Oxidized phospholipids (OxPL) are present within atherosclerotic plaques and bound by lipoprotein (a) [Lp(a)] in plasma. This study evaluated the impact of atorvastatin on oxidized LDL (OxLDL) in patients with acute coronary syndromes (ACS).

METHODS AND RESULTS

OxLDL-E06 (OxPL content on apolipoprotein B-100 [apoB] detected by antibody E06), apoB-100 immune complexes (apoB-IC), OxLDL autoantibodies, and Lp(a) levels were measured in 2341 patients at baseline and after 16 weeks of treatment with atorvastatin 80 mg/d or placebo. The OxLDL-E06 and apoB-IC data are reported per apoB-100 particle (OxPL/apoB, IC/apoB) and as total levels on all apoB-100 particles (total apoB-OxPL and total apoB-IC [eg, OxPL/apoB or IC/apoBxapoB-100 levels]). Compared with baseline values, atorvastatin reduced apoB-100 (-33%), total apoB-OxPL (-29.7%), total apoB-IC IgG (-29.5%), and IgM (-25.7%) (P<0.0001 for all), whereas no change or an increase was observed with placebo. When normalized per apoB-100, compared with placebo, atorvastatin increased OxPL/apoB (9.5% versus -3.9%, P<0.0001) and Lp(a) (8.8% versus -0.7%, (P<0.0001). A strong correlation was noted between OxPL/apoB and Lp(a) (R=0.85, P<0.0001), consistent with previous data that Lp(a) binds OxPL.

CONCLUSIONS

After atorvastatin treatment, total OxPL on all apoB-100 particles was decreased. However, there was enrichment of OxPL on a smaller pool of apoB-100 particles, in parallel with similar increases in Lp(a), suggesting binding by Lp(a). These data support the hypothesis that atorvastatin promotes mobilization and clearance of proinflammatory OxPL, which may contribute to a reduction in ischemic events after ACS.

Identification of novel molecular candidates for fatty liver in the hyperlipidemic mouse model, HcB19

The inbred HcB19 mouse strain expresses a truncated form of thioredoxin interacting protein and is phenotypically characterized by fatty liver and elevated plasma triglycerides and VLDL. Recently, these mice have been proposed as an animal model for familial combined hyperlipidemia. The aim of the present study was identification of hepatic proteins specifically associated with the presence of fatty liver. Eighteen differential proteins were detected in whole-liver homogenate from HcB19, or the parental strain C3H, using 2D electrophoresis, and 11 of those were successfully identified by mass spectrometry. Five of the identified differential proteins were mitochondrial, two peroxisomal, two cytosolic, and two secretory. Four differential proteins were novel in the fatty liver proteome [i.e., aconitase, succinate dehydrogenase, propionyl CoA carboxylase alpha chain (PCCA), and 3-hydroxyanthranilate 3,4 dioxygenase (3HAAO)]. Of these, PCCA and 3HAAO are of particular interest because of their known functions in nicotinic acid metabolism (3HAAO) and ketogenesis (PCCA). We have newly identified several differential proteins in the hepatic proteome of mice with fatty liver, including PCCA and 3HAAO, and confirmed differential expression of previously reported proteins. These individual proteins, PCCA and 3HAAO, can be important in development of fatty liver or in the expression of hyperlipidemia.

Management of selected lipid abnormalities: hypertriglyceridemia, isolated low HDL-cholesterol, lipoprotein(a), and lipid abnormalities in renal diseases and following solid organ transplantation

Although the focus in treating lipid disorders is on reducing LDL-C levels, additional lipid-related independent risk factors, such as TG, HDL-C, and Lp(a) levels, should be used clinically to assess cardiovascular risk. Decisions to initiate drug therapy for LDL-C reduction may be influenced by levels of these other lipoprotein fractions. Data supporting intervention to modify these factors are less abundant than for LDL-C reduction, but in certain circumstances. drug therapy targeted at TGs or HDL-C may be appropriate. Patients who have nephrotic syndrome and end-stage renal disease are at particularly high risk for the development of CVD and should be treated aggressively for their lipid disorders. Finally, solid organ transplant recipients are almost always hyperlipidemic and appropriate therapy could reduce cardiovascular events.

Comparison of the dose-response relationships of 2 lipid-lowering agents: a Bayesian meta-analysis

BACKGROUND

Comparing the dose-response of a new drug to that of a previously studied drug can aid in understanding their relative potencies. Two dose-finding studies addressed the effect of a new drug, rosuvastatin, on its ability to decrease low-density lipoprotein cholesterol (LDL-C) levels. One of these studies included 2 doses of atorvastatin, and substantial additional information is available in the literature about the effect of atorvastatin on LDL-C level lowering.

METHODS

The 2 dose-finding studies of rosuvastatin considered otherwise healthy patients who had hypercholesterolemia. Comparable studies of atorvastatin were identified via a MEDLINE search in December 1999. Multiple reviewer consensus identified 15 of 41 studies on atorvastatin published since 1996 that met these selection criteria: reporting of LDL-C level change from baseline at least 6 weeks after treatment initiation, doses administered, and treatment group sizes. Eligible populations had clinical evidence of hypercholesterolemia. We excluded studies with patients who had severe illness or a previous history of transplantation. Data extraction of the mean, sample sizes, and SDs (or CIs) by dose was carried out independently by multiple reviewers. We combined the results from the various studies with Bayesian hierarchical modeling and analyzed them with Markov chain Monte Carlo techniques.

RESULTS

Combining this study and literature results substantially increased the power to compare the dose-response relationships of rosuvastatin and atorvastatin. Rosuvastatin reduced LDL-C level by an estimated 10 to 17 percentage points more than atorvastatin when both were given at the same dose. Approximately one quarter of the dose of rosuvastatin achieved about the same magnitude of LDL-C level reduction as atorvastatin at dosages as high as 80 mg. This finding does not imply a 4-fold difference in efficacy overall and specifically does not describe the results at higher dosage levels.

CONCLUSIONS

Bayesian meta-analysis of results from related studies allows the comparison of the dose-response relationships of 2 drugs, better estimates of a particular dose-response relationship within an individual study, and the expression of relative benefits (of dose and drug) in terms of probabilities. Explicitly comparing a study's results with historical data using Bayesian meta-analysis allows clinicians to view the study in the larger context of medical research.

Atorvastatin lowers lipoprotein(a) but not apolipoprotein(a) fragment levels in hypercholesterolemic subjects at high cardiovascular risk

The effect of statins on Lp(a) levels is controversial; furthermore, the potential action of statins on apo(a) fragmentation is indeterminate. We therefore determined the circulating levels of Lp(a) and of apo(a) fragments in hypercholesterolemic patients before and after treatment (6 weeks) with Atorvastatin 10 mg/day (A10) or Simvastatin 20 mg/day (S20). In a double blind study, hypercholesterolemic patients (n=391) at high cardiovascular risk (LDL-C>=4.13 mmol/l; TG<2.24 mmol/l; 34% with documented CHD; 45% hypertensive; and 29% current smokers) were assigned to treatment with A10 (n=199) or S20 (n=192). Plasma Lp(a) and apo(a) fragment levels (n=206) were measured prior to and after treatment. At baseline, A10 and S20 groups did not differ in plasma levels of lipids, Lp(a) (A10: 0.45+/-0.48 mg/ml, S20: 0.46+/-0.5), and apo(a) fragments (A10: 3.88+/-5.22 microg/ml; S20: 3.25+/-3), and equally in apo(a) isoform size (A10: 26+/-5 kr, S20: 25.5+/-5.3). After treatment, both statins significantly reduced Lp(a) levels (A10: 0.42+/-0.47 mg/ml, 6% variation, P<0.001; S20: 0.45+/-0.53 mg/ml, 0.02% variation, P=0.046). A10 and S20 did not significantly differ in their efficacy to lower Lp(a) levels. In a multivariate logistic regression analysis, the reduction of Lp(a) levels was independently associated with Lp(a) baseline concentration, but not to other variables, including LDL-C reduction. Plasma levels of apo(a) fragments were not modified by either statin. In conclusion, both A10 and S20 significantly lowered Lp(a), although this effect was of greater magnitude in atorvastatin-treated patients.

Long term efficacy and safety of atorvastatin in the treatment of severe type III and combined dyslipidaemia

BACKGROUND

Fibric acid derivatives and HMG-CoA reductase inhibitors are effective in combination for treating patients with familial dysbetalipoproteinaemia and severe combined dyslipidaemia, but combination therapy affects compliance and increases the risk of side effects.

AIM

To evaluate the efficacy and safety of monotherapy with atorvastatin, an HMG-CoA reductase inhibitor with superior efficacy in lowering low density lipoprotein cholesterol and triglyceride concentrations, in patients with dysbetalipoproteinaemia and severe combined dyslipidaemia.

METHODS

Atorvastatin was tested as single drug treatment in 36 patients with familial dysbetalipoproteinaemia and 23 patients with severe combined dyslipidaemia.

RESULTS

After 40 weeks of 40 mg atorvastatin treatment decreases in total cholesterol, triglycerides, and apolipoprotein B of 40%, 43%, and 41%, respectively, were observed in the combined dyslipidaemia group, and of 46%, 40%, and 43% in the dysbetalipoproteinaemic patients. Target concentrations of total cholesterol (< 5 mmol/l) were reached by 63% of the patients, and target concentrations of triglycerides (< 3.0 mmol/l) by 66%. Treatment with atorvastatin was well tolerated and no serious side effects were reported.

CONCLUSIONS

Atorvastatin is very effective as monotherapy in the treatment of familial dysbetalipoproteinaemia and severe combined dyslipidaemia.

Effects of micronized fenofibrate versus atorvastatin in the treatment of dyslipidaemic patients with low plasma HDL-cholesterol levels: a 12-week randomized trial

BACKGROUND

Studies have suggested that raising low levels of high-density lipoprotein cholesterol (HDL-C) may be an important target for the prevention of coronary heart disease.

OBJECTIVE

To compare the ability of micronized fenofibrate and atorvastatin to increase plasma HDL-C levels.

DESIGN

Multicentre, randomized open-label study. Settings. The study was conducted in 19 centres across the UK and Canada.

SUBJECT

One hundred and eighty-one patients were randomized and the full analysis set included 165 nondiabetic patients with low HDL-C (women <46 mg dL-1, i.e. 1.2 mmol L-1 and men <43 mg dL-1, i.e. 1.1 mmol L-1): 86 patients in the atorvastatin group and 79 patients in the micronized fenofibrate group. Interventions. Micronized fenofibrate (200 mg day-1, 87 patients) or atorvastatin (10 mg day-1, 94 patients) for a period of 12 weeks. Main outcome measures. Percent change in HDL-C levels.

RESULT

After 12 weeks of treatment, the mean percent change from baseline in HDL-C was significantly higher in the micronized fenofibrate group (13.3%) compared with the atorvastatin group (5.3%, P=0.0003). The magnitude of such relative change was inversely related to the baseline HDL-C levels only in the micronized fenofibrate group. Furthermore, in the fenofibrate treatment group, 50.9% of the patients (29 of 57 patients) with a baseline HDL-C <40 mg dL-1 achieved a plasma HDL-C level above 40 mg dL-1 after 12 weeks of treatment versus 27.9% of the patients (19 of 68 patients) in the atorvastatin group (P=0.01).

CONCLUSIONS

On the basis of (1) the greater impact of fenofibrate than atorvastatin on HDL-C levels and (2) the greater proportion of dyslipidemic patients achieving HDL-C levels above 40 mg dL-1 with fenofibrate than atorvastatin, it is suggested that micronized fenofibrate should be considered as a good therapeutic option to treat dyslipidemic patients with low HDL-C and moderately elevated LDL-C concentrations.

Atorvastatin: an updated review of its pharmacological properties and use in dyslipidaemia

Atorvastatin is a synthetic hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor. In dosages of 10 to 80 mg/day, atorvastatin reduces levels of total cholesterol, low-density lipoprotein (LDL)-cholesterol, triglyceride and very low-density lipoprotein (VLDL)-cholesterol and increases high-density lipoprotein (HDL)-cholesterol in patients with a wide variety of dyslipidaemias. In large long-term trials in patients with primary hypercholesterolaemia. atorvastatin produced greater reductions in total cholesterol. LDL-cholesterol and triglyceride levels than other HMG-CoA reductase inhibitors. In patients with coronary heart disease (CHD), atorvastatin was more efficacious than lovastatin, pravastatin. fluvastatin and simvastatin in achieving target LDL-cholesterol levels and, in high doses, produced very low LDL-cholesterol levels. Aggressive reduction of serum LDL-cholesterol to 1.9 mmol/L with atorvastatin 80 mg/day for 16 weeks in patients with acute coronary syndromes significantly reduced the incidence of the combined primary end-point events and the secondary end-point of recurrent ischaemic events requiring rehospitalisation in the large. well-designed MIRACL trial. In the AVERT trial, aggressive lipid-lowering therapy with atorvastatin 80 mg/ day for 18 months was at least as effective as coronary angioplasty and usual care in reducing the incidence of ischaemic events in low-risk patients with stable CHD. Long-term studies are currently investigating the effects of atorvastatin on serious cardiac events and mortality in patients with CHD. Pharmacoeconomic studies have shown lipid-lowering with atorvastatin to be cost effective in patients with CHD, men with at least one risk factor for CHD and women with multiple risk factors for CHD. In available studies atorvastatin was more cost effective than most other HMG-CoA reductase inhibitors in achieving target LDL-cholesterol levels. Atorvastatin is well tolerated and adverse events are usually mild and transient. The tolerability profile of atorvastatin is similar to that of other available HMG-CoA reductase inhibitors and to placebo. Elevations of liver transaminases and creatine phosphokinase are infrequent. There have been rare case reports of rhabdomyolysis occurring with concomitant use of atorvastatin and other drugs.

CONCLUSION

Atorvastatin is an appropriate first-line lipid-lowering therapy in numerous groups of patients at low to high risk of CHD. Additionally it has a definite role in treating patients requiring greater decreases in LDL-cholesterol levels. Long-term studies are under way to determine whether achieving very low LDL-cholesterol levels with atorvastatin is likely to show additional benefits on morbidity and mortality in patients with CHD.

The placebo effect and randomized trials: analysis of alternative medicine

Randomized controlled trials are generally regarded as the gold standard of study designs to determine causality. The inclusion of a placebo group in these trials, when appropriate, is critical to access the efficacy of a drug or supplement. The placebo response itself has received some attention in the medical literature over the past fifty years. The recent increasing utilization of dietary supplements and herbal medications by patients makes it imperative to reevaluate the placebo response in conventional and alternative medicine. This article will review some of the negative and positive results from randomized trials utilizing dietary supplements (androstenedione, beta-carotene, CoQ10, garlic, soy, vitamin C and E...) for a number of non-urologic and urologic conditions, including cancer.

Asessing coronary heart disease risk and managing lipids

Elevated low-density lipoprotein (LDL) and below normal high-density lipoprotein (HDL) cholesterol are risk factors for coronary heart disease (CHD). According to clinical guidelines, LDL cholesterol is the primary target for lipid-altering therapy. Many patients who develop CHD have LDL and HDL cholesterol levels that fall within the desirable or low-risk category; consequently, conventional measurements of plasma lipids may not accurately detect high-risk patients. This article discusses the clinical significance of lipoprotein subclasses and methods of measurement. Assessing lipoprotein subclasses provides a more comprehensive and efficacious therapeutic approach compared with the standard lipid profile.

Effect of statin therapy on remnant lipoprotein cholesterol levels in patients with combined hyperlipidemia

Clinical trials with statins have demonstrated significant reductions in cardiovascular events. Remnant lipoproteins are independent predictors of cardiovascular events. Because of the paucity of data on the effect of statins on remnant lipoproteins, we tested the effect of pravastatin, simvastatin, and atorvastatin on remnant lipoprotein cholesterol (RLP-C) levels in a randomized crossover study in patients with combined hyperlipidemia. After a 6-week diet phase, patients (n=22) were randomized to pravastatin (40 mg/d), simvastatin (20 mg/d), or atorvastatin (10 mg/d) for 6 weeks, with a 3-week washout between each drug. All 3 drugs significantly decreased total and low density lipoprotein (LDL) cholesterol (P<0.001). Mean reduction in LDL cholesterol with pravastatin, simvastatin, and atorvastatin was 21%, 29%, and 32%, respectively. None of the drugs affected high density lipoprotein cholesterol levels. Median levels of triglycerides were significantly reduced with simvastatin (26%, P=0.001) and atorvastatin (24%, P=0.0001) but not with pravastatin (9%, P=0.18). Non-high density lipoprotein cholesterol decreased significantly with all 3 statins (20%, 29%, and 32% with pravastatin, simvastatin, and atorvastatin, respectively; P<0.001). Median RLP-C levels were significantly reduced with simvastatin (6%, P<0.05) and atorvastatin (25.9%, P<0.001) but not with pravastatin (2.9%, P=0.58). Thus, atorvastatin and simvastatin, in addition to reducing LDL cholesterol and triglyceride levels, significantly reduced RLP-C levels. This could be another potential mechanism to explain their cardiovascular benefits.

Effect of niacin and atorvastatin on lipoprotein subclasses in patients with atherogenic dyslipidemia

This study was conducted to determine the efficacy of atorvastatin and niacin on lipoprotein subfractions in patients with atherogenic dyslipidemia. This was a multicenter, randomized, open-label, parallel-design study of patients with total cholesterol >200 mg/dl, triglycerides between 200 and 800 mg/dl, and apolipoprotein B >110 mg/dl. Patients were randomly assigned to atorvastatin 10 mg or immediate release niacin 3,000 mg daily for 12 weeks following a low-fat diet stabilization period. Lipoprotein subclasses were measured by nuclear magnetic resonance spectroscopy. Atorvastatin and niacin both significantly reduced the concentrations of very low-density lipoprotein (VLDL) particles (-31% and -29%, respectively) and small low-density lipoprotein (LDL) particles (-44% and -35%, respectively). Niacin increased the concentration of large LDL (+75%). Atrovastatin reduced the number of LDL particles more than niacin (31% vs 14%). In patients with atherogenic dyslipidemia, both drugs had important effects on lipoprotein subfractions, which contributed to a reduction in coronary heart disease risk. The drugs equally reduced VLDL subclass levels. Niacin shifted the LDL subclass distribution toward the larger particles, more effectively converted patients from LDL phenotype B to phenotype A, and increased levels of the larger and perhaps more cardioprotective high-density lipoprotein particles. In contrast, atorvastatin preferentially lowered the concentration of small LDL particles without increasing levels of large LDL, and more effectively, reduced LDL particle numbers. Atorvastatin had a preferred LDL effect, whereas niacin had a preferred high-density lipoprotein effect.

Comparison of efficacy and safety of atorvastatin (10mg) with simvastatin (10mg) at six weeks. ASSET Investigators

The 6-week efficacy and safety of atorvastatin versus simvastatin was determined during a 54-week, open-label, multicenter, parallel-arm, treat-to-target study. In all, 1,424 patients with mixed dyslipidemia (triglyceride 200 to 600 mg/dl [2.26 to 6.77 mmol/L]) were stratified to 1 of 2 groups (diabetes or no diabetes). Patients were then randomized to receive either atorvastatin 10 mg/ day (n = 730) or simvastatin 10 mg/day (n = 694). Efficacy was determined by measuring changes from baseline in lipid parameters including low-density lipoprotein (LDL) cholesterol, total cholesterol, triglycerides, and apolipoprotein B. Compared with simvastatin, atorvastatin produced significantly greater (p < 0.0001) reductions from baseline in LDL cholesterol (37.2% vs 29.6%), total cholesterol (27.6% vs 21.5%), triglycerides (22.1% vs 16.0%), the ratio of LDL cholesterol to high-density lipoprotein (HDL) cholesterol (41.1% vs 33.7%), and apolipoprotein B (28.3% vs 21.2%), and a comparable increase from baseline in HDL cholesterol (7.4% vs 6.9%). Atorvastatin was also significantly (p < 0.0001) more effective than simvastatin at treating the overall patient population to LDL cholesterol goals (55.6% vs 38.4%). Fewer than 6% of patients in either treatment group experienced drug-attributable adverse events, which were mostly mild to moderate in nature. Diabetic patients treated with either statin had safety characteristics similar to nondiabetics, with atorvastatin exhibiting superior efficacy to simvastatin. In conclusion, atorvastatin, at a dose of 10 mg/day, is more effective than simvastatin 10 mg/day at lowering lipids and reaching LDL cholesterol goals in patients with mixed dyslipidemia. Both statins are well tolerated with safety profiles similar to other members of the statin class.

The benefits of niacin in atherosclerosis

Niacin favorably alters all major lipid subfractions at pharmacologic doses. Alone or in combination, it promotes regression of coronary artery disease, decreases coronary events, stroke, and total mortality. Major recent progress in niacin is in four areas. Firstly, recent data indicate that it increases high-density lipoprotein (HDL) and lowers triglycerides and low-density lipoprotein (LDL) by mechanisms different from statins, fibrates, and bile-sequestrants, giving rationale for combination therapy to achieve synergistic effects for complete lipid goal achievement. Secondly, new data on an extended-release preparation of niacin given once nightly indicates that it is as effective and has greater tolerability than immediate-release niacin. Thirdly, preliminary data with a single tablet formulation extended-release niacin and an HMG CoA reductase inhibitor (lovastatin) shows it to be safe and very effective, especially for raising HDL. Finally, emerging evidence indicates that niacin can be used effectively and safely in patients with type 2 diabetes mellitus, who often have low HDL levels.

Action of atorvastatin in combined hyperlipidemia : preferential reduction of cholesteryl ester transfer from HDL to VLDL1 particles

Combined hyperlipidemia (CHL) is characterized by a concomitant elevation of plasma levels of triglyceride-rich, very low density lipoproteins (VLDLs) and cholesterol-rich, low density lipoproteins (LDLs). The predominance of small, dense LDLs contributes significantly to the premature development of coronary artery disease in patients with this atherogenic dyslipoproteinemia. In the present study, we evaluated the impact of atorvastatin, a newly developed inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase, on the cholesteryl ester transfer protein (CETP)-mediated remodeling of apolipoprotein (apo) B-containing lipoprotein subspecies, and more specifically, the particle subpopulations of VLDL and LDL in CHL. In parallel, we evaluated the atorvastatin-induced modulation of the quantitative and qualitative features of atherogenic apo B-containing and cardioprotective apo AI-containing lipoprotein subspecies. Atorvastatin therapy (10 mg/d for a 6-week period) in patients with a lipid phenotype typical of CHL (n=18) induced reductions of 31% (P<0.0001) and 36% (P<0.0001) in plasma total cholesterol and LDL cholesterol, respectively. In addition, atorvastatin significantly reduced VLDL cholesterol, triglycerides, and apo B levels by 43% (P<0.0001), 27% (P=0.0006), and 31% (P<0.0001), respectively. The plasma concentrations of triglyceride-rich lipoproteins (VLDL1, Sf 60 to 400; VLDL2, Sf 20 to 60; and intermediate density lipoproteins, Sf 12 to 20) and of LDL, as determined by chemical analysis, were markedly diminished after drug therapy (-30% and -28%, respectively; P<0.0007). Atorvastatin significantly reduced circulating levels of all major LDL subspecies, ie, light (-28%, P<0.0008), intermediate (-27%, P<0.0008), and dense (-32%, P<0.0008) LDL; moreover, in terms of absolute lipoprotein mass, the reduction in dense LDL levels (mean -62 mg/dL) was preponderant. In addition, the reduction in plasma dense LDL concentration after therapy was significantly correlated with a reduction in plasma VLDL1 levels (r=0.429, P=0.0218). Atorvastatin induced a significant reduction (-7%, P=0.0039) in total CETP-dependent CET activity, which accurately reflects a reduction in plasma CETP mass concentration. Total CETP-mediated CET from high density lipoproteins to apo B-containing lipoproteins was significantly reduced (-26%, P<0.0001) with drug therapy. Furthermore, CETP activity was significantly correlated with the atorvastatin-induced reduction in plasma VLDL1 levels (r=0.456, P=0. 0138). Indeed, atorvastatin significantly and preferentially decreased CET from HDL to the VLDL1 subfraction (-37%, P=0.0064), thereby reducing both the levels (-37%, P=0.0001) and the CE content (-20%, P<0.005) of VLDL1. We interpret our data to indicate that 2 independent but complementary mechanisms may be operative in the atorvastatin-induced reduction of atherogenic LDL levels in CHL: first, a significant degree of normalization of both the circulating levels and the quality of their key precursors, ie, VLDL1, and second, enhanced catabolism of the major LDL particle subclasses (ie, light, intermediate, and dense LDL) due to upregulation of hepatic LDL receptors.

Management of selected lipid abnormalities. Hypertriglyceridemia, low HDL cholesterol, lipoprotein(a), in thyroid and renal diseases, and post-transplantation

Although the focus in treating lipid disorders is on reducing LDL cholesterol levels, triglycerides, HDL cholesterol, and Lp(a) are all independent risk factors that can be used clinically to assess cardiovascular risk. Decisions to initiate drug therapy for LDL cholesterol reduction may be influenced by levels of these other lipoprotein fractions. Data supporting intervention to modify these factors is less abundant than for LDL cholesterol reduction, but in certain circumstances drug therapy targeted at triglycerides or HDL cholesterol may be appropriate. Patients with nephrotic syndrome and end-stage renal disease are at particularly high risk for the development of cardiovascular disease and should be treated aggressively for lipid disorders. Finally, solid organ transplant recipients are almost always hyperlipidemic, and appropriate therapy could reduce cardiovascular events.

Atorvastatin in the treatment of primary hypercholesterolemia and mixed dyslipidemias

OBJECTIVE

To review the efficacy and safety of atorvastatin in the treatment of dyslipidemias.

DATA SOURCES

A MEDLINE search (January 1960-April 1998), Current Contents search, additional references listed in articles, and unpublished data obtained from the manufacturer were used to identify data from scientific literature. Studies evaluating atorvastatin (i.e., abstracts, clinical trials, proceedings, data on file with the manufacturer) were considered for inclusion.

STUDY SELECTION

English-language literature was reviewed to evaluate the pharmacology, pharmacokinetics, therapeutic use, and adverse effects of atorvastatin. Additional relevant citations were used in the introductory material and discussion.

DATA EXTRACTION

Open and controlled animal and human clinical studies published in the English-language literature were reviewed and evaluated. Clinical trials selected for inclusion were limited to those in human subjects and included data from animals if human data were not available.

DATA SYNTHESIS

Atorvastatin is a recent hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor for the treatment of primary hypercholesterolemia, mixed dyslipidemias, and homozygous familial hypercholesterolemia. In patients who have not met the low-density lipoprotein cholesterol (LDL-C) goal as recommended by the National Cholesterol Education Program Adult Treatment Panel II guidelines, atorvastatin 10-80 mg/d may be used as monotherapy or as an adjunct to other lipid-lowering agents and dietary modifications. In placebo-controlled clinical trials, atorvastatin 10-80 mg/d lowered LDL-C by 35-61% and triglyceride (TG) concentrations by 14-45%. In comparative trials, atorvastatin 10-80 mg/d showed a greater reduction of serum total cholesterol (TC), LDL-C, TG concentrations, and apolipoprotein B-100 (apo B) compared with pravastatin, simvastatin, or lovastatin. In comparison, currently available HMG-CoA reductase inhibitors (lovastatin, simvastatin, pravastatin, fluvastatin, cerivastatin) lower LDL-C concentrations by approximately 20-40% and TG concentrations by approximately 10-30%. In pooled placebo-controlled clinical trials of up to a duration of 52 weeks, atorvastatin in dosages up to 80 mg/d appeared to be well tolerated. The most common adverse effect of atorvastatin was gastrointestinal upset. The incidence of elevated serum hepatic transaminases may be greater at higher dosages of atorvastatin. The risk of myopathy and/or rhabdomyolysis is increased when an HMG-CoA reductase inhibitor is taken concomitantly with cyclosporine, gemfibrozil, niacin, erythromycin, or azole antifungals.

CONCLUSIONS

Atorvastatin appears to reduce TC, LDL-C, TG concentrations, and apo B to a greater extent than do currently available HMG-CoA reductase inhibitors. Atorvastatin may be preferred in patients requiring greater than a 30% reduction in LDL-C or in patients with both elevated LDL-C and TG concentrations, which may obviate the need for combination lipid-lowering therapy. Adverse effects of atorvastatin appear to be similar to those of other HMG-CoA reductase inhibitors and should be routinely monitored. Long-term safety data (> 1 y) on atorvastatin compared with other HMG-CoA reductase inhibitors are still needed. Cost-effectiveness studies comparing atorvastatin with other HMG-CoA reductase inhibitors remain a subject for further investigation. Published clinical studies evaluating the impact of atorvastatin on cardiovascular morbidity and mortality are still needed. Additionally, clinical studies evaluating the impact of lipid-lowering therapy in a larger number of women, the elderly (> 70 y), and patients with diabetes for treatment of primary and secondary prevention of coronary heart disease are needed.