Correlation of non-high-density lipoprotein cholesterol and low-density lipoprotein cholesterol with apolipoprotein B during simvastatin + fenofibrate therapy in patients with combined hyperlipidemia (a subanalysis of the SAFARI trial)

Non-HDL-cholesterol in dyslipidemia: Review of the state-of-the-art literature and outlook

Dyslipidemia refers to unhealthy changes in blood lipid composition and is a risk factor for atherosclerotic cardiovascular diseases (ASCVD). Usually, low-density lipoprotein-cholesterol (LDL-C) is the primary goal for dyslipidemia management. However, non-high-density lipoprotein cholesterol (non-HDL-C) has gained attention as an alternative, reliable goal. It encompasses all plasma lipoproteins like LDL, triglyceride-rich lipoproteins (TRL), TRL-remnants, and lipoprotein a [Lp(a)] except high-density lipoproteins (HDL). In addition to LDL-C, several other constituents of non-HDL-C have been reported to be atherogenic, aiding the pathophysiology of atherosclerosis. They are acknowledged as contributors to residual ASCVD risk that exists in patients on statin therapy with controlled LDL-C levels. Therefore, non-HDL-C is now considered an independent risk factor or predictor for CVD. The popularity of non-HDL-C is attributed to its ease of estimation and non-dependency on fasting status. It is also better at predicting ASCVD risk in patients on statin therapy, and/or in those with obesity, diabetes, and metabolic disorders. In addition, large follow-up studies have reported that individuals with higher baseline non-HDL-C at a younger age (<45 years) were more prone to adverse CVD events at an older age, suggesting a predictive ability of non-HDL-C over the long term. Consequently, non-HDL-C is recommended as a secondary goal for dyslipidemia management by most international guidelines. Intriguingly, geographical patterns in recent epidemiological studies showed remarkably high non-HDL-C attributable mortality in high-risk countries. This review highlights the independent role of non-HDL-C in ASCVD pathogenesis and prognosis. In addition, the need for a country-specific approach to dyslipidemia management at the community/population level is discussed. Overall, non-HDL-C can become a co-primary or primary goal in dyslipidemia management.

β-Carotene Oxygenase 1 Activity Modulates Circulating Cholesterol Concentrations in Mice and Humans

BACKGROUND

Plasma cholesterol is one of the strongest risk factors associated with the development of atherosclerotic cardiovascular disease (ASCVD) and myocardial infarction. Human studies suggest that elevated plasma β-carotene is associated with reductions in circulating cholesterol and the risk of myocardial infarction. The molecular mechanisms underlying these observations are unknown.

OBJECTIVE

The objective of this study was to determine the impact of dietary β-carotene and the activity of β-carotene oxygenase 1 (BCO1), which is the enzyme responsible for the conversion of β-carotene to vitamin A, on circulating cholesterol concentration.

METHODS

In our preclinical study, we compared the effects of a 10-d intervention with a diet containing 50 mg/kg of β-carotene on plasma cholesterol in 5-wk-old male and female C57 Black 6 wild-type and congenic BCO1-deficient mice. In our clinical study, we aimed to determine whether 5 common small nucleotide polymorphisms located in the BCO1 locus affected serum cholesterol concentrations in a population of young Mexican adults from the Universities of San Luis Potosí and Illinois: A Multidisciplinary Investigation on Genetics, Obesity, and Social-Environment (UP AMIGOS) cohort.

RESULTS

Upon β-carotene feeding, Bco1-/- mice accumulated >20-fold greater plasma β-carotene and had ∼30 mg/dL increased circulating total cholesterol (P < 0.01) and non-HDL cholesterol (P < 0.01) than wild-type congenic mice. Our results in the UP AMIGOS cohort show that the rs6564851 allele of BCO1, which has been linked to BCO1 enzymatic activity, was associated with a reduction in 10 mg/dL total cholesterol concentrations (P = 0.009) when adjusted for vitamin A and carotenoid intakes. Non-HDL-cholesterol concentration was also reduced by 10 mg/dL when the data were adjusted for vitamin A and total carotenoid intakes (P = 0.002), or vitamin A and β-carotene intakes (P = 0.002).

CONCLUSIONS

Overall, our results in mice and young adults show that BCO1 activity impacts circulating cholesterol concentration, linking vitamin A formation with the risk of developing ASCVD.

Apolipoprotein B is a risk factor for end-stage renal disease

Background

Apolipoprotein B (ApoB), a constituent of lipid particles, is known to increase the risk of cardiovascular diseases. However, the association between ApoB and end-stage renal disease (ESRD) remains to be resolved. Our objective was to determine whether the ApoB concentration has an association with the risk of ESRD.

Methods

Serum ApoB, ApoA1, conventional lipid parameters and lipid subfractions were analyzed in 9403 subjects. The hazard ratio (HR) for the risk of ESRD was calculated using tertiles of ApoB concentration.

Results

ESRD developed in 110 patients (1.2%) during 10 years of follow-up. Several lipid parameters were compared for their association with the risk of ESRD, of which ApoB was best and its relationship was also independent of other clinical parameters. Individuals in the second and third ApoB tertiles had a higher risk of ESRD than those in the first tertile, with HRs of 1.5 [95% confidence interval (CI) 0.89–2.61] and 2.6 (1.56–4.20), respectively. A high ApoB:ApoA1 ratio was associated with a higher risk of ESRD, but ApoA1 had no independent association. Even after adjusting the competing risk for all-cause death, high ApoB concentrations had an association with the risk of ESRD.

Conclusions

High ApoB concentration is associated with a higher risk of ESRD, despite adjustment for other lipid and clinical parameters. Accordingly, the monitoring of ApoB may be helpful for the prediction of ESRD.

Assessing Atherosclerotic Cardiovascular Disease Risk with Advanced Lipid Testing: State of the Science

Cardiovascular disease is the number one cause of death and disability worldwide. While substantial gains have been made in reducing cardiovascular mortality, future projections suggest that we have reached a nadir and may be at an inflection point, given the rising tide of obesity and diabetes. Evaluation and management of plasma lipids is central to the prevention of atherosclerotic cardiovascular disease. Although the standard lipid panel represents a well-established platform to assess risk, this test alone can be insufficient and/or misleading. Advances in our understanding of atherosclerosis have led to the development of lipid-based biomarkers that help to discriminate the risk of cardiovascular disease when it is unclear. While these biomarkers provide novel information, their implementation into clinical medicine remains difficult given discrepancies in the literature, lack of assay standardisation, poor accessibility and high cost. However, additional measures of atherogenic lipoproteins or their surrogates may offer insight beyond the standard lipid panel, providing a more precise assessment of risk and more accurate assessment of lipid-lowering therapy.

[Outcomes of revascularizing operations on lower-limb arteries in patients with critical ischaemia and multifocal atherosclerosis]

The purpose of this study was to evaluate the amputation-free survival rate and predictors of major adverse cardiovascular events (extracardiac and cardiac mortality, non-fatal myocardial infarction, non-fatal stroke) in patients with atherosclerotic occlusive-stenotic lesions of the femoropopliteal-tibial segment and critical ischaemia. We analysed the results of treating a total of 122 patients with atherosclerotic lesions of the superficial femoral artery and lower limb critical ischaemia. Of these, 35 patients had no lesions of other arterial basins, 24 patients presented with a concomitant lesion of the carotid basin, 41 subjects had lesions of the coronary basin, and 22 had lesions of the coronary and carotid basins. The patients were subjected to either bypass graft operation (n=75) or endovascular intervention (n=47). The evaluated outcome measures were amputation-free survival and the frequency of major adverse cardiovascular events. The average duration of follow up amounted to 38.2±4.3 months. The carried out multivariate logistic regression analysis demonstrated that the factors associated with lower limb amputation and the development of major adverse cardiovascular events were as follows: a concomitant lesion of the coronary (p=0.044) and coronary-carotid (p<0.05) basins, a history of endured myocardial infarction (p=0.003), a C-reactive protein level not less than 17.0 mg/l (p<0.05) and the value of the apolipoprotein B/A1 ratio above 1.0 (p=0.004).

Non-HDL cholesterol should not generally replace LDL cholesterol in the management of hyperlipidaemia

PURPOSE OF REVIEW

Non-HDL cholesterol was originally conceived as a therapeutic target for statin treatment in hypertriglyceridaemia when apolipoprotein B100 assays were not widely available. Recently non-HDL cholesterol has been recommended to replace LDL cholesterol in the clinical management of dyslipidaemia routinely in general medical practice. This is misguided.

RECENT FINDINGS

Non-HDL cholesterol is heterogeneous, constituting a mixture of triglyceride-rich VLDL, intermediate density lipoprotein and LDL in which small dense LDL is poorly represented and to which VLDL cholesterol contributes increasingly as triglyceride levels rise. This makes it unsuitable as a goal of lipid-lowering treatment or as an arbiter of who should receive such treatment. Results of trials designed to lower LDL cholesterol are not easily translated to non-HDL cholesterol. Fasting is no longer thought essential for screening the general population for raised LDL cholesterol. ApoB100 measurement also does not require fasting even in rarer more extreme lipoprotein disorders encountered in the Lipid Clinic, provides greater precision and specificity and overcomes the problems posed by LDL and non-HDL cholesterol. It is more easily interpreted both in diagnosis and as a therapeutic goal and it includes SD-LDL.

SUMMARY

If we are to discourage use of LDL cholesterol, it should be in favour of apoB100 not non-HDL cholesterol.

Fenofibrate/simvastatin fixed-dose combination in the treatment of mixed dyslipidemia: safety, efficacy, and place in therapy

Lipids disorder is the principal cause of atherosclerosis and may present with several forms, according to blood lipoprotein prevalence. One of the most common forms is combined dyslipidemia, characterized by high levels of triglycerides and low level of high-density lipoprotein. Single lipid-lowering drugs may have very selective effect on lipoproteins; hence, the need to use multiple therapy against dyslipidemia. However, the risk of toxicity is a concerning issue. In this review, the effect and safety of an approved combination therapy with simvastatin plus fenofibrate are described, with an analysis of pros and cons resulting from randomized multicenter trials, meta-analyses, animal models, and case reports as well.

Effects of extended-release niacin/laropiprant on correlations between apolipoprotein B, LDL-cholesterol and non-HDL-cholesterol in patients with type 2 diabetes

BACKGROUND

LDL-C, non-HDL-C and ApoB levels are inter-correlated and all predict risk of atherosclerotic cardiovascular disease (ASCVD) in patients with type 2 diabetes mellitus (T2DM) and/or high TG. These levels are lowered by extended-release niacin (ERN), and changes in the ratios of these levels may affect ASCVD risk. This analysis examined the effects of extended-release niacin/laropiprant (ERN/LRPT) on the relationships between apoB:LDL-C and apoB:non-HDL-C in patients with T2DM.

METHODS

T2DM patients (n = 796) had LDL-C ≥1.55 and <2.97 mmol/L and TG <5.65 mmol/L following a 4-week, lipid-modifying run-in (~78 % taking statins). ApoB:LDL-C and apoB:non-HDL-C correlations were assessed after randomized (4:3), double-blind ERN/LRPT or placebo for 12 weeks. Pearson correlation coefficients between apoB:LDL-C and apoB:non-HDL-C were computed and simple linear regression models were fitted for apoB:LDL-C and apoB:non-HDL-C at baseline and Week 12, and the correlations between measured apoB and measured vs predicted values of LDL-C and non-HDL-C were studied.

RESULTS

LDL-C and especially non-HDL-C were well correlated with apoB at baseline, and treatment with ERN/LRPT increased these correlations, especially between LDL-C and apoB. Despite the tighter correlations, many patients who achieved non-HDL-C goal, and especially LDL-C goal, remained above apoB goal. There was a trend towards greater increases in these correlations in the higher TG subgroup, non-significant possibly due to the small number of subjects.

CONCLUSIONS

ERN/LRPT treatment increased association of apoB with LDL-C and non-HDL-C in patients with T2DM. Lowering LDL-C, non-HDL-C and apoB with niacin has the potential to reduce coronary risk in patients with T2DM.

High triglyceride levels alter the correlation of apolipoprotein B with low- and non-high-density lipoprotein cholesterol mostly in individuals with diabetes or metabolic syndrome

OBJECTIVE

To assess the correlation of Apolipoprotein B (Apo-B) with low-density (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) in untreated individuals attending a lipid clinic.

METHODS

This was a retrospective study conducted in Greece and including 1000 dyslipidemic subjects. We included individuals not taking lipid-lowering therapy at baseline visit and divided them in 2 groups: subjects diagnosed with diabetes or fulfilling the criteria of metabolic syndrome (MetS) and hyperlipidemic subjects without diabetes or MetS. The correlations (r(2)) of Apo-B with LDL-C and non-HDL-C were assessed in these 2 groups. Further analyses were performed according to the baseline triglyceride (TG) levels (<and ≥200 mg/dL).

RESULTS

From 821 eligible subjects, 51% were diagnosed with diabetes or MetS. The correlations between Apo-B and LDL-C or non-HDL-C were similar for the individuals with TG < 200 mg/dL. Specifically, Apo-B was significantly correlated with LDL-C (r(2) = 0.755, p < 0.01, for those with diabetes or MetS; r(2) = 0.848, p < 0.01, for non-diabetic and no MetS hyperlipidemic subjects). The corresponding correlations between Apo-B and non-HDL-C for the 2 groups were 0.743 and 0.838, respectively (p < 0.01). Although these correlations remained significant for the individuals with high TG levels (≥200 mg/dL), the correlation factor was markedly decreased mostly in those with diabetes or MetS (r(2) = 0.600, p < 0.01, for the correlation between Apo-B and LDL-C; r(2) = 0.604, p < 0.01, for the correlation between Apo-B and non-HDL-C); in contrast, the corresponding correlations were stronger in the non-diabetic and no MetS hyperlipidemic individuals (r(2) = 0.710 and 0.714, respectively, p < 0.01).

CONCLUSION

Apo-B correlation with both LDL-C and non-HDL-C is reduced in individuals with high TG levels and in particular for those with diabetes or MetS.

Metabolic syndrome update

The metabolic syndrome is a multiplex risk factor for atherosclerotic cardiovascular disease and type 2 diabetes. It is composed of atherogenic dyslipidemia, elevated blood pressure, insulin resistance and elevated glucose, a pro-thrombotic state, and a pro-inflammatory state. Excess energy intake and concomitant obesity are the major drivers of the syndrome. Lifestyle intervention can reverse metabolic risk factors, but at times, drug therapies or bariatric surgery may be required to control more overt risk factors.

National lipid association recommendations for patient-centered management of dyslipidemia: part 1--full report

The leadership of the National Lipid Association convened an Expert Panel to develop a consensus set of recommendations for patient-centered management of dyslipidemia in clinical medicine. An Executive Summary of those recommendations was previously published. This document provides support for the recommendations outlined in the Executive Summary. The major conclusions include (1) an elevated level of cholesterol carried by circulating apolipoprotein B-containing lipoproteins (non-high-density lipoprotein cholesterol and low-density lipoprotein cholesterol [LDL-C], termed atherogenic cholesterol) is a root cause of atherosclerosis, the key underlying process contributing to most clinical atherosclerotic cardiovascular disease (ASCVD) events; (2) reducing elevated levels of atherogenic cholesterol will lower ASCVD risk in proportion to the extent that atherogenic cholesterol is reduced. This benefit is presumed to result from atherogenic cholesterol lowering through multiple modalities, including lifestyle and drug therapies; (3) the intensity of risk-reduction therapy should generally be adjusted to the patient's absolute risk for an ASCVD event; (4) atherosclerosis is a process that often begins early in life and progresses for decades before resulting a clinical ASCVD event. Therefore, both intermediate-term and long-term or lifetime risk should be considered when assessing the potential benefits and hazards of risk-reduction therapies; (5) for patients in whom lipid-lowering drug therapy is indicated, statin treatment is the primary modality for reducing ASCVD risk; (6) nonlipid ASCVD risk factors should also be managed appropriately, particularly high blood pressure, cigarette smoking, and diabetes mellitus; and (7) the measurement and monitoring of atherogenic cholesterol levels remain an important part of a comprehensive ASCVD prevention strategy.

Effects of extended-release niacin/laropiprant, simvastatin, and the combination on correlations between apolipoprotein B, LDL cholesterol, and non-HDL cholesterol in patients with dyslipidemia

BACKGROUND

Statins modify correlations between apolipoprotein B (apoB) and low-density lipoprotein cholesterol (LDL-C) and apoB and non-high-density lipoprotein cholesterol (non-HDL-C); however, it is not known whether niacin-based therapies have similar effects.

OBJECTIVE

To evaluate the effects of extended-release niacin (ERN)/laropiprant (LRPT), simvastatin (SIMVA), and ERN/LRPT + SIMVA (pooled ERN/LRPT + SIMVA) on apoB:LDL-C and apoB:non-HDL-C correlations in dyslipidemic patients.

METHODS

This post-hoc analysis of a 12-week study evaluated the apoB:LDL-C and apoB:non-HDL-C correlations in dyslipidemic patients randomized equally to double-blind ERN/LRPT 1 g/20 mg, SIMVA 10, 20, or 40 mg, or ERN/LRPT 1 g/20 mg + SIMVA (10, 20, or 40 mg) once daily for 4 weeks. At week 5, doses were doubled in all groups except SIMVA 40 mg (unchanged) and ERN/LRPT 1 g/20 mg + SIMVA 40 mg (switched to ERN/LRPT 2 g/40 mg + SIMVA 40 mg). Simple linear regression analyses were used to calculate LDL-C and non-HDL-C levels corresponding to known apoB baseline values (ie, in untreated patients) and following treatment.

RESULTS

The apoB:LDL-C and apoB:non-HDL-C correlations were higher and the predicted LDL-C and non-HDL-C levels for a known apoB value were considerably lower following treatment with ERN/LRPT, SIMVA and ERN/LRPT + SIMVA compared with untreated patients at baseline.

CONCLUSION

Greater dissociation of apoB, LDL-C, and non-HDL-C targets occur following treatment with ERN/LRPT, SIMVA, and ERN/LRPT + SIMVA in patients with dyslipidemia. The achievement of more aggressive LDL-C and non-HDL-C goals in patients receiving lipid-modifying therapy may further reduce coronary risk by normalizing apoB-containing atherogenic lipoproteins.

Effects of ezetimibe, simvastatin and ezetimibe/simvastatin on correlations between apolipoprotein B, LDL cholesterol and non-HDL cholesterol in patients with primary hypercholesterolemia

BACKGROUND/SYNOPSIS

Apolipoprotein (apo) B is highly predictive of coronary risk, especially in patients with high triglycerides (TG). This post hoc analysis evaluated the effects of lipid-lowering therapy on correlations between apoB and low-density lipoprotein cholesterol (apoB:LDL-C) and non-high-density lipoprotein cholesterol (apoB:non-HDL-C) in patients with TG< and ≥ 200 mg/dL.

METHODS

This analysis used data from 3 randomized clinical trials in patients with primary hypercholesterolemia receiving placebo, ezetimibe (EZE), simvastatin (SIMVA) or EZE/SIMVA for 12 weeks. Simple linear regression analyses predicted LDL-C and non-HDL-C levels corresponding to apoB values (80 mg/dL) at baseline and Week 12.

RESULTS

ApoB correlated with LDL-C (r ≥ 0.76) and non-HDL-C (r ≥ 0.86) at baseline. The correlations were strengthened with SIMVA and EZE/SIMVA at Week 12 (r ≥ 0.88 for LDL-C and r ≥ 0.94 for non-HDL-C). The predicted LDL-C and non-HDL-C values were lower following treatment with SIMVA or EZE/SIMVA than for placebo and EZE. For SIMVA and EZE/SIMVA, the predicted LDL-C and non-HDL-C values were closer to more aggressive LDL-C and non-HDL-C levels (i.e., 70 and 100 mg/dL, respectively). The apoB:LDL-C and apoB:non-HDL-C correlations were weaker and the predicted LDL-C values were generally lower in high TG patients than in low TG patients both at baseline and Week 12. In contrast, the predicted non-HDL-C values were generally higher in high versus low TG patients at baseline but less so at Week 12.

CONCLUSION

After treatment with EZE, SIMVA, or EZE/SIMVA, a given apoB value corresponds to lower LDL-C and non-HDL-C levels than those obtained from untreated patients.

The impact of serum lipids on risk for microangiopathy in patients with type 2 diabetes mellitus

Background

Few large-scale, real-world studies have assessed the relative associations of lipid fractions with diabetic microvascular events. The main objective of this study was to evaluate the association of the lipid profile components, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), and non-high density lipoprotein cholesterol (non-HDL-C) with microvascular complications (MVCs) in type 2 diabetes mellitus (T2DM) patients.

Methods

This observational cohort study queried the HealthCore Integrated Research Database (HIRD^SM) for newly-diagnosed (Index Date) 18-64-year-old patients with diabetes mellitus between 01/01/2005-06/30/2010. Inclusion required ≥12 months pre-index continuous health plan eligibility and ≥1 pre-index lipid profile result. Patients with polycystic ovary syndrome and prior MVCs were excluded. Incident complications were defined as the earliest occurrence of diabetic retinopathy, peripheral neuropathy, and/or nephropathy post-index. Cox proportional models and Kaplan-Meier (KM) curves were used to evaluate associations among variables.

Results

Of the patients (N = 72,267), 50.05 % achieved HDL-C, 64.28 % LDL-C, 59.82 % TG, and 56.79 % non-HDL-C American Diabetes Association goals at baseline. During follow-up (mean, 21.74 months), there were 5.21 microvascular events per 1,000 patient-months. A 1-mg/dL increase in HDL-C was associated with 1 % decrease in any MVC risk (P < .0001), but for LDL-C, TG, and non-HDL-C, 1-mg/dL increase resulted in increases of 0.2 % (P < .0001), 0.1 % (P < 0.001) and 0.3 % (P < 0.001) in MVC risk. Patients achieving HDL-C goals had a 11 % lower risk of MVC versus non-achievers (RR 0.895, [95 % CI, 0.852-0.941], P < .0001). Similarly, TG goal attainment was associated with a lowered risk for any MVC (RR 0.849, [95 % CI, 0.808-0.892], P < .0001). Evaluation of KM survival curves demonstrated no significant difference in the risk of MVCs between patients achieving vs. not achieving LDL-C goals, but did demonstrate a difference in MVC risk between patients achieving vs. not achieving non-HDL-C goals.

Conclusion

This study demonstrates significant independent associations among lipid fractions and risk for microangiopathy. These findings suggest that attaining established ADA goals for HDL-C, TG, and non-HDL-C may reduce risk for microvascular events among patients with diabetes.

Opening a new lipid "apo-thecary": incorporating apolipoproteins as potential risk factors and treatment targets to reduce cardiovascular risk

Statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) represent the cornerstone of drug therapy to reduce low-density lipoprotein (LDL) cholesterol and cardiovascular risk. However, even optimal statin management of LDL cholesterol leaves many patients with residual cardiovascular risk, in part because statins are more effective in reducing LDL cholesterol than apolipoprotein B (Apo B). Apo B may be a better marker of atherogenic risk than LDL cholesterol because Apo B measures the total number of all atherogenic particles (total atherosclerotic burden), including LDL, very low-density lipoprotein, intermediate-density lipoprotein, remnant lipoproteins, and lipoprotein(a). To determine whether Apo B is a better indicator of baseline cardiovascular risk and residual risk after lipid therapy compared with LDL cholesterol, a MEDLINE search of the literature published in English from January 1, 1975, through December 1, 2010, was conducted. On the basis of data from most population studies, elevated Apo B was more strongly associated with incident coronary heart disease than similarly elevated LDL cholesterol. Apo B was also a superior benchmark (vs LDL cholesterol) of statins' cardioprotective efficacy in both primary-prevention and secondary-prevention trials. To minimize cardiovascular risk among persons with hypercholesterolemia or dyslipidemia, the best available evidence suggests that intensive therapy with statins should be initiated to achieve the lowest possible Apo B level (with adequate drug toleration) and then other therapies (eg, niacin, bile acid resins, ezetimibe) added to potentiate these Apo B-lowering effects. In future consensus lipid-lowering treatment guidelines, Apo B should be considered as an index of residual risk, a potential parameter of treatment efficacy, and a treatment target to minimize risk of coronary heart disease.

Fenofibrate plus simvastatin (fixed-dose combination) for the treatment of dyslipidaemia

INTRODUCTION

Statin use results in a significant reduction of cardiovascular disease (CVD) risk. However, patients still have residual CVD risk, even if they are receiving optimal statin treatment.

AREAS COVERED

This review, based on a Pubmed/Scopus search, discusses the available evidence regarding the use of a fixed-dose fenofibrate plus simvastatin combination. This combination is useful for patients with mixed dyslipidaemia because it improves the overall lipoprotein profile. Although in clinical trials the rate of adverse events was not significantly greater than monotherapy, patients who receive combination treatment should be monitored carefully. Furthermore, in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Study, this combination did not result in a significant reduction of CVD events compared with simvastatin monotherapy. However, a possible benefit in this trial was observed in the subgroup of patients with high triglyceride and low high-density lipoprotein cholesterol levels.

EXPERT OPINION

The fixed-dose fenofibrate plus simvastatin combination treatment produces additive results and is safe when patients are properly monitored. Existing evidence appears to support the addition of fenofibrate to simvastatin treatment for the reduction of residual CVD risk in patients with atherogenic dyslipidaemia. However, this combination did not lead to better clinical outcomes in the absence of dyslipidaemia.

Comparisons of apolipoprotein B levels estimated by immunoassay, nuclear magnetic resonance, vertical auto profile, and non-high-density lipoprotein cholesterol in subjects with hypertriglyceridemia (SAFARI Trial)

Low-density lipoprotein (LDL) cholesterol and triglyceride-rich lipoproteins constitute non-high-density lipoprotein (non-HDL) cholesterol. These are atherogenic lipoproteins and non-HDL cholesterol is a secondary target of treatment beyond LDL cholesterol in patients with hypertriglyceridemia. Some investigators favor total apolipoprotein B over non-HDL cholesterol as the secondary target of treatment. This is based on publications suggesting that total apolipoprotein B is more predictive of cardiovascular events than non-HDL cholesterol. Several methods are available for estimating total apolipoprotein B. This study compared total apolipoprotein estimated by immunonephelometric assay (INA), vertical auto profile (VAP), nuclear magnetic resonance (NMR), and non-HDL cholesterol levels in patients with hypertriglyceridemia from the previously reported Simvastatin plus Fenofibrate for Combined Hyperlipidemia (SAFARI) trial. Total apolipoprotein B levels were found to be highest by INA, intermediate by NMR and non-HDL cholesterol, and lowest by VAP. Concordance for non-HDL cholesterol levels among the INA, VAP, and NMR methods was better than that for total apolipoprotein B levels; the correlation between non-HDL cholesterol and apolipoprotein B by INA was strongest (0.929). In patients with a low triglyceride/HDL cholesterol ratio (<3.5), total apolipoprotein B determined by INA was higher than that estimated from non-HDL cholesterol levels, whereas in patients with a high triglyceride/HDL C ratio (≥3.5), apolipoprotein B predicted using non-HDL cholesterol was in better agreement with INA-determined apolipoprotein B levels. Similar trends were observed with VAP using equations specific for LDL particle size. In conclusion, more work is needed to improve agreement of apolipoprotein B measurements among methods employed clinically. Non-HDL cholesterol is also useful to predict total apolipoprotein B and some improvement may be attained by taking into account the ratio of triglyceride/HDL cholesterol as a measurement of LDL particle size.

Influence of simvastatin, fenofibrate and/or ezetimibe on correlation of low-density lipoprotein and nonhigh-density lipoprotein cholesterol with apolipoprotein B in mixed dyslipidemic patients

OBJECTIVES

Correlations between low-density lipoprotein cholesterol (LDL-C), or nonhigh-density lipoprotein cholesterol (non-HDL-C) and apolipoprotein B (Apo B) change after statin therapy has been initiated in hypercholesterolemic patients. This post-hoc analysis studied the correlation between these parameters in patients with mixed dyslipidemia before and after receiving lipid-lowering treatment.

RESULTS

Data from two randomized, double-blind studies of 1112 patients with mixed dyslipidemia receiving treatment (ezetimibe 10 mg, ezetimibe/simvastatin 10/20 mg, fenofibrate 160 mg, ezetimibe + fenofibrate 10/160 mg, or ezetimibe/simvastatin + fenofibrate 10/20/160 mg) were pooled. Correlation analyses and simple linear regression analyses were performed at baseline in untreated patients and after 12 weeks of treatment in the whole pooled population, the treatment groups, and after stratification by baseline triglyceride levels (150-250, ≥ 250 mg/dL) within the treatment groups. Both LDL-C and non-HDL-C were closely correlated with levels of Apo B at baseline, and these correlations improved after treatment. When using the fitted simple linear regression equations, we found that the on-treatment LDL-C and non-HDL-C levels corresponding to an Apo B of 90, 80, and 70 mg/dL were lower than proposed LDL-C and non-HDL-C treatment targets. For TG ≥ 250 mg/dL, the corresponding LDL-C was generally lower than that for triglycerides 150-250 mg/dL, except in the cases with fenofibrate in the treatment.

CONCLUSION

The results of these analyses suggest that achieving goal-specified levels of Apo B in statin-treated patients with mixed dyslipidemia would require more aggressive LDL-C lowering to achieve the greatest reduction in LDL particle number.

'Trig-onometry': non-high-density lipoprotein cholesterol as a therapeutic target in dyslipidaemia

Targeting elevations in low-density lipoprotein cholesterol (LDL-C) remains the cornerstone of cardiovascular prevention. However, this fraction does not adequately capture elevated triglyceride-rich lipoproteins (TRLs; e.g. intermediate-density lipoprotein, very low density lipoprotein) in certain patients with metabolic syndrome or diabetic dyslipidaemia. Many such individuals have residual cardiovascular risk that might be lipid/lipoprotein related despite therapy with first-line agents (statins). Epidemiological evidence encompassing > 100,000 persons supports the contention that non-high-density lipoprotein cholesterol (non-HDL-C) is a superior risk factor vs. LDL-C for incident coronary heart disease (CHD) in certain patient populations. In studies with clinical end-points evaluated in the current article, a 1:1 to 1:3 relationship was observed between reductions in non-HDL-C and in the relative risk of CHD after long-term treatment with statins, niacin (nicotinic acid) and fibric-acid derivatives (fibrates); this relationship increased to 1:5 to 1:10 in smaller subgroups of patients with elevated triglycerides and low HDL-C levels. Treatment with statin-, niacin-, fibrate-, ezetimibe-, and omega 3 fatty acid-containing regimens reduced non-HDL-C by approximately 9-65%. In a range of clinical trials, long-term treatment with these agents also significantly decreased the incidence of clinical/angiographic/imaging efficacy outcome variables. For patients with dyslipidaemia, consensus guidelines have established non-HDL-C treatment targets 30 mg/dl higher than LDL-C goals. Ongoing prospective randomised controlled trials should help to resolve controversies concerning (i) the clinical utility of targeting non-HDL-C in patients with dyslipidaemia; (ii) the most efficacious and well-tolerated therapies to reduce non-HDL-C (e.g. combination regimens); and (iii) associations between such reductions and clinical, angiographic, and/or imaging end-points.

Dyslipidaemia in the metabolic syndrome and type 2 diabetes: pathogenesis, priorities, pharmacotherapies

IMPORTANCE OF THE FIELD

Dyslipoproteinaemia is a cardinal feature of the metabolic syndrome that accelerates atherosclerosis. It is usually characterized by high plasma concentrations of triglyceride-rich and apolipoprotein B (apoB)-containing lipoproteins, with depressed concentrations of high-density lipoprotein (HDL). Drug interventions are essential for normalizing metabolic dyslipidaemia.

AREAS COVERED IN THIS REVIEW

This review discusses the mechanisms and treatment for dyslipidaemia in the metabolic syndrome and type 2 diabetes.

WHAT THE READER WILL GAIN

A comprehensive understanding of the pathophysiology and pharmacotherapy of dyslipidaemia in the metabolic syndrome and diabetes.

TAKE HOME MESSAGE

Dysregulation of lipoprotein metabolism may be due to a combination of overproduction of triglyceride-rich lipoproteins, decreased catabolism of apoB-containing particles, and increased catabolism of HDL particles. These abnormalities may be consequent on a global metabolic effect of insulin resistance and an excess of both visceral and hepatic fat. Lifestyle modifications may favourably alter lipoprotein transport in the metabolic syndrome. Patients with dyslipidaemia and established cardiovascular disease should receive a statin as first-line therapy. Combination with other lipid-regulating agents, such as ezetimibe, fibrates, niacins and fish oils may optimize the benefit of statin on atherogenic dyslipidaemia.