Why is non−high-density lipoprotein cholesterol a better marker of the risk of vascular disease than low-density lipoprotein cholesterol?

Association of non-HDL cholesterol with plaque burden and composition of culprit lesion in acute coronary syndrome. An intravascular ultrasound-virtual histology study

OBJECTIVE

Lipids play key role in coronary atherosclerosis. The role of non-high-density lipoprotein cholesterol (non-HDL-C) in atherosclerotic plaques using intravascular imaging remains unclear. This study aimed to assess its relationship with coronary plaque features using intravascular ultrasound (IVUS) in acute coronary syndrome (ACS).

METHODS

A total of 601 patients divided into two groups: normal non-HDL-C≤130 mg/dl (n = 410) and high non-HDL cholesterol >130 mg/dl (n = 191). IVUS performed before coronary intervention.

RESULTS

Mean age 53.18 ± 12.29 years. No significant differences in hypertension, diabetes, and smoking between groups. Plaque burden was significantly higher among normal versus high non-HDL-C groups (79.59 ± 9.98 % vs. 81.61 ± 5.39 %; p = 0.001). At minimal luminal site, fibrofatty percentage was higher in normal non-HDL-C group (p = 0.027), while necrotic core greater in high non-HDL-C group (p = 0.033). Segmental analysis, necrotic core was significantly higher in percentage (p = 0.006) and volumes (p = 0.011) in normal versus high non-HDL-C groups. Total cholesterol (r = 0.099, p = 0.015), LDL-C (r = 0.081, p = 0.046), triglycerides (r = 0.083, p = 0.041),and non-HDL-C (r = 0.099, p = 0.015) positively correlated with plaque burden. Total cholesterol (r = 0.115, p = 0.005), LDL-C (r = 0.107, p = 0.009), and non-HDL-C (r = 0.105, p = 0.010) positively correlated with necrotic core volume. Linear regression analysis showed age and non-HDL-C as predictors of higher plaque burden. Multiple linear regression analysis; age, body mass index, and non-HDL-C were predictors of larger necrotic core volume.

CONCLUSION

Non-HDL-C levels were positively associated with plaque burden, measure of extent of atherosclerosis. It is closely associated with and is a predictor of necrotic core volume; a marker of plaque vulnerability. This IVUS study demonstrates potential role of non-HDL-C in causation of plaque in ACS.

Measurement of Serum Low Density Lipoprotein Cholesterol and Triglyceride-Rich Remnant Cholesterol as Independent Predictors of Atherosclerotic Cardiovascular Disease: Possibilities and Limitations

The serum low density lipoprotein cholesterol (LDL-C) concentration is the dominant clinical parameter to judge a patient's risk of developing cardiovascular disease (CVD). Recent evidence supports the theory that cholesterol in serum triglyceride-rich lipoproteins (TRLs) contributes significantly to the atherogenic risk, independent of LDL-C. Therefore, combined analysis of both targets and adequate treatment may improve prevention of CVD. The validity of TRL-C calculation is solely dependent on the accuracy of the LDL-C measurement. Direct measurement of serum LDL- C is more accurate than established estimation procedures based upon Friedewald, Martin-Hopkins, or Sampson equations. TRL-C can be easily calculated as total C minus high density lipoprotein C (HDL-C) minus LDL-C. Enhanced serum LDL-C or TRL-C concentrations require different therapeutic approaches to lower the atherogenic lipoprotein C. This review describes the different atherogenic lipoproteins and their possible analytical properties and limitations.

Residual Atherosclerotic Cardiovascular Disease Risk: Focus on Non-High-Density Lipoprotein Cholesterol

Cardiovascular disease (CVD) caused by atherosclerosis is the leading cause of death worldwide. The level of low-density lipoprotein cholesterol (LDL-C), considered as the initiator of atherosclerosis, is the most widely used predictor for CVD risk and LDL-C has been the primary target for lipid-lowering therapies. However, residual CVD risk remains high even with very low levels of LDL-C. This residual CVD risk may be due to remnant cholesterol, high triglyceride levels, and low high-density lipoprotein cholesterol (HDL-C). Non-high density lipoprotein cholesterol (non-HDL-C), which is calculated as total cholesterol minus HDL-C (and represents the cholesterol content of all atherogenic apolipoprotein B-containing lipoproteins), has emerged as a better risk predictor for CVD than LDL-C and an alternative target for CVD risk reduction. Major international guidelines recommend evaluating non-HDL-C as part of atherosclerotic CVD risk assessment, especially in people with high triglycerides, diabetes, obesity, or very low LDL-C. A non-HDL-C target of <130 mg/dL (3.4 mmol/L) has been recommended for patients at very high risk, which is 30 mg/dL (0.8 mmol/L) higher than the corresponding LDL-C target goal. Non-HDL-C lowering approaches include reducing LDL-C and triglyceride levels, increasing HDL-C, or targeting multiple risk factors simultaneously. However, despite the growing evidence for the role of non-HDL-C in residual CVD risk, and recommendations for its assessment in major guidelines, non-HDL-C testing is not routinely done in clinical practice. Thus, there is a need for increased awareness of the need for non-HDL-C testing for ascertaining CVD risk and concomitant prevention of CVD.

From Dietary Cholesterol to Blood Cholesterol, Physiological Lipid Fluxes, and Cholesterol Homeostasis

Dietary cholesterol (C) is a major contributor to the endogenous C pool, and it affects the serum concentration of total C, particularly the low-density lipoprotein cholesterol (LDL-C). A high serum concentration of LDL-C is associated with an increased risk for atherosclerosis and cardiovascular diseases. This concentration is dependent on hepatic C metabolism creating a balance between C input (absorption and synthesis) and C elimination (conversion to bile acids and fecal excretion). The daily C absorption rate is determined by dietary C intake, biliary C secretion, direct trans-intestinal C excretion (TICE), and the fractional C absorption rate. Hepatic C metabolism coordinates C fluxes entering the liver via chylomicron remnants (CMR), LDL, high-density lipoproteins (HDL), hepatic C synthesis, and those leaving the liver via very low-density lipoproteins (VLDL), biliary secretion, and bile acid synthesis. The knowns and the unknowns of this C homeostasis are discussed.

Evaluation of Beneficial and Adverse Effects of a Diet Supplemented with Schisandrae Fructus Seed Ethanol Extract on Lipid and Glucose Metabolism in Normal and Hypercholesterolemic/Hyperglycemic Mice

Schisandrae Fructus (SF), the fruit of Schisandra chinensis (Turcz.) Baillon, has been used for the treatment of liver injury and metabolism-related disorders in China. The objective of this study was to investigate the effects of supplementation with ethanol extract of SF seed (EtSF-S) on serum/hepatic lipid and glucose levels as well as fecal total cholesterol (TC) contents in mice fed a normal diet (ND) or high-fat/fructose diet (HFFD) containing 15% lard oil and 15% fructose. Female ICR mice (18–20 g in body weight) were fed with ND or HFFD for 3 months, and then EtSF-S was added to both chow diets at increasing concentrations of 1, 5, and 10% (w/w). Thirty days later, serum and hepatic lipids, including TC, triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and glucose, were measured. Dietary supplementation with EtSF-S reduced hepatic TC (36 and 18%) and TG levels (38 and 28%) and increased serum HDL/LDL ratio (16 and 26%) in both ND- and HFFD-fed mice, respectively. Moreover, supplementation with EtSF-S elevated serum HDL (31%) in HFFD-fed mice and reduced serum LDL (27%) in ND-fed mice. EtSF-S treatment reduced fat mass (40%) in ND-fed mice and increased fecal TC contents (33%) in HFFD-fed mice. EtSF-S supplementation decreased hepatic glucose contents (29%) in both ND- and HFFD-fed mice. However, diet supplemented with EtSF-S elevated serum TG levels (up to 123%) and hepatic size (28%), but more importantly, suppressed the body weight gain (approximately 130%) in mice fed with HFFD. These findings suggested that dietary supplementation with EtSF-S as natural herbal function food may be a useful strategy for the treatment of patients with fatty liver disease or overweight without a high intake of sugar and fat.

Discordance of Low-Density Lipoprotein Cholestrol and Non-High-Density Lipoprotein Cholestrol and Coronary Artery Disease Severity

BACKGROUND

A sizeable proportion of patients have discordant low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C).

OBJECTIVES

We assessed the relationship between discordance of LDL-C and non-HDL-C and coronary artery disease (CAD) severity.

METHODS

We retrospectively evaluated the data of 574 consecutive patients who underwent coronary angiography. Fasting serum lipid profiles were recorded, SYNTAX and Gensini scores were calculated to establish CAD complexity and severity. We determined the medians for LDL-C and non-HDL-C to examine the discordance between LDL-C and non-HDL-C. Discordance was defined as LDL-C greater than or equal to the median and non-HDL-C less than median; or LDL-C less than median and non-HDL-C greater than or equal to median. A p value < 0.05 was accepted as statistically significant.

RESULTS

LDL-C levels were strongly and positively correlated with non-HDL-C levels (r = 0.865, p < 0.001) but 15% of patients had discordance between LDL-C and non-HDL-C. The percentage of patients with a Gensini score of zero or SYNTAX score of zero did not differ between discordant or concordant groups (p = 0.837, p = 0.821, respectively). Mean Gensini and SYNTAX scores, percentage of patients with Gensini score ≥20 and SYNTAX score >22 were not different from group to group (p = 0.635, p = 0.733, p = 0.799, p = 0.891, respectively). Also, there was no statistically significant correlation between LDL-C and Gensini or SYNTAX scores in any of the discordant or concordant groups. Additionally, no correlation was found between non-HDL-C and Gensini or SYNTAX score.

CONCLUSIONS

While there was discordance between LDL-C and non-HDL-C (15% of patients), there is no difference regarding CAD severity and complexity between discordant and concordant groups.

Association between non-high-density lipoprotein cholesterol and haemorrhagic transformation in patients with acute ischaemic stroke

BACKGROUND

It is unclear whether non-high-density lipoprotein cholesterol (Non-HDL-C) is associated with haemorrhagic transformation (HT) after acute ischaemic stroke (AIS). We aimed to explore the association between Non-HDL-C and HT, as well as compare the predictive values of Non-HDL-C and low-density lipoprotein cholesterol (LDL-C) for HT.

METHODS

We consecutively enrolled AIS patients within 7 days of stroke onset. Participants were divided into four categories according to quartiles of Non-HDL-C. HT was assessed by follow-up brain imaging. We assessed the association between Non-HDL-C, LDL-C and HT in multivariate logistic regression analysis.

RESULTS

A total of 2043 patients were included, among whom 232 were identified as HT. Compared with the highest quartiles, the first, second and third quartiles of Non-HDL-C were associated with increased risk of HT (adjusted odds ratios [ORs] 1.74 [95% confidence interval [CI] 1.09-2.78], 2.01[95% CI 1.26-3.20], and 1.76 [95% CI 1.10-2.83], respectively, P for trend = 0.024). Similar results were found for LDL-C. There was significant interaction between Non-HDL-C and age (P for interaction = 0.021). The addition of Non-HDL-C and LDL-C to conventional factors significantly improved predictive values [Non-HDL-C, net reclassification index (NRI) 0.24, 95%CI 0.17-0.31, P < 0.001; LDL-C, NRI 0.15, 95%CI 0.08-0.22, P = 0.03].

CONCLUSIONS

Low Non-HDL-C was associated with increased risks of HT. In addition, Non-HDL-C has similar effects as LDL-C for predicting HT.

Impact of Lipid-Lowering Therapy on Mortality According to the Baseline Non-HDL Cholesterol Level: A Meta-Analysis

INTRODUCTION

Previous report showed that more intensive lipid-lowering therapy was associated with less mortality when baseline LDL-C levels were > 100 mg/dL. Non-HDL-C is a better predictor of cardiovascular risk than simpler LDL-C.

AIM

The objective of this meta-analysis was to define the impact of lipid-lowering therapy on the reduction of total and cardiovascular mortality by different baseline levels of non-HDL-C.

METHODS

We performed a meta-analysis including randomized, controlled clinical trials of lipid-lowering therapy, reporting mortality with a minimum of 6 months of follow-up, searching in PubMed/Medline, EMBASE and Cochrane Clinical Trials databases. The random-effects model and meta-regression were performed.

RESULTS

Twenty nine trials of lipid-lowering drugs, including 233,027 patients, were considered eligible for the analyses. According to the baseline non-HDL-C level, the results on cardiovascular mortality were: (1) ≥ 190 mg/dL: OR 0.63 (95% CI 0.53-0.76); (2) 160-189 mg/dL: OR 0.82 (95% CI 0.75-0.89); (3) 130-159 mg/dL: OR 0.71 (95% CI 0.52-0.98); (4) < 130 mg/dL: OR 0.95 (95% CI 0.87-1.05). When evaluating mortality from any cause, the results were the following: (1) ≥ 190 mg/dL: OR 0.70 (95% CI 0.61-0.82); (2) 160-189 mg/dL: OR 0.91 (95% CI 0.83-0.98); (3) 130-159 mg/dL; OR 0.88 (95% CI 0.77-1.00); (4) < 130 mg/dL: OR 0.98 (95% CI 0.91-1.06). The meta-regression analysis showed a significant association between baseline non-HDL-C and mortality.

CONCLUSIONS

In these meta-analyses, lipid-lowering therapy was associated with reduction in the risk of all-cause and cardiovascular mortality when baseline non-HDL-C levels were above than 130 mg/dL.

Association Between Lipid Profiles and Arterial Stiffness in Chinese Patients With Hypertension: Insights From the CSPPT

Arterial stiffness plays a key role in the pathogenesis of cardiovascular disease. However, the relationship between lipid levels and arterial stiffness is controversial. We aimed to investigate the association between lipid parameters and brachial-ankle pulse-wave velocity (baPWV) in Chinese patients with hypertension. A total of 14 071 participants with hypertension in the China Stroke Primary Prevention Trial (CSPPT) were enrolled in the present study. Patients were assigned to 4 equal groups according to their baPWV. Participants in the highest baPWV group were older with a higher prevalence of stroke and diabetes mellitus as well as higher body mass index (BMI), blood pressure, fasting plasma glucose, uric acid, total cholesterol (TC), triglycerides (TG), homocysteine (Hcy), and vitamin B12 levels ( P < .001). After adjusting for age, sex, BMI, and other cardiovascular risks, high-density lipoprotein cholesterol (HDL-C) was negatively related to baPWV (β = -0.22, P = .012), TC (β = 0.08, P = 0.001), TG (β = 0.14, P = .001); non-HDL-C (β = 0.12, P = .001) and positively related to baPWV. The effect was not observed for low-density lipoprotein cholesterol (LDL-C; β = 0.12, P = .335).These results suggested that non-HDL-C, TG, and TC were associated with arterial stiffness in a Chinese population with hypertension. HDL-C was inversely associated with arterial stiffness.

Non-high-density lipoprotein cholesterol and risk of cardiovascular disease in the general population and patients with type 2 diabetes: A systematic review and meta-analysis

AIMS

To examine the relationship of non-high-density lipoprotein cholesterol (non-HDL-C) level with cardiovascular disease (CVD) risk in type 2 diabetes patients and the general population by conducting a meta-analysis.

METHODS

We made a comprehensive literature search for relevant observational studies investigating the relationship of non-HDL-C level with CVD risk in the general population and type 2 diabetes patients using the PubMed and Embase databases. Pooled risk ratio (RR) with 95% confidence intervals (CI) was calculated for the highest versus the reference lower non-HDL-Cl.

RESULTS

A total of 13 studies with 156,381 individuals were included. The pooled RR of CVD was 1.59 (95% CI 1.46-1.72) in the general population and 1.99 (95% CI 1.57-2.51) in type 2 diabetes patients. Subgroup analysis showed the similar effect of non-HDL-C on CVD risk between men (RR1.98; 95% CI 1.70-2.30) and women (RR 1.63; 95% CI 1.35-1.96). However, elevated non-HDL-C was not associated with higher risk of cardiovascular mortality in the general population (RR 1.64; 95% CI 0.96-2.80) and type 2 diabetes patients (RR 1.08; 95% CI 0.57-2.07).

CONCLUSIONS

Elevated non-HDL-C level is associated with an increased risk of CVD in the general population and type 2 diabetes patients.

Threshold Effects in the Relationship Between Serum Non-High-Density Lipoprotein Cholesterol and Metabolic Syndrome

BACKGROUND

Previous studies have suggested that the non-high-density lipoprotein cholesterol (non-HDL-C) is strongly associated with metabolic syndrome (MetS); however, the explicit relationship between them has not yet been clarified. The aim of this study was to reveal the explicit association between the non-HDL-C with MetS.

METHODS

The present study was based on a cross-sectional study, which was carried out in Spain. A total of 60,799 workers were recruited between 2012 and 2016. Anthropometric parameters and blood indices (lipid profile and fasting blood glucose) were collected. Participants were divided into the MetS group or the non-MetS group based on the criteria of the National Cholesterol Education Program Adult Treatment Panel III. The relationship between serum non-HDL-C and the risk of MetS was evaluated using multivariate regression analysis, piece-wise linear regression analysis, smooth curve fitting and threshold saturation effect analysis after adjustment of potential confounders.

RESULTS

The risk of developing MetS increased with increasing non-HDL-C level. However, this association was only presented in the range of the non-HDL-C concentrations from 118 mg/dl to 247 mg/dl after adjusting for potential confounders. When compared to lower non-HDL-C level (<118 mg/dl), higher levels of non-HDL-C (118-247 mg/dl and >247 mg/dl) were related to higher incidence of MetS, with adjusted odds ratio (95% confidence interval) of 3.08 (2.77, 3.42) and 17.18 (14.29, 20.65), respectively (P for trend <0.05).

CONCLUSION

Higher serum non-HDL-C level was associated with increased MetS incidence; however, significant threshold saturation effects were observed when the non-HDL-C level <118 mg/dl or >247 mg/dl.

What Serum Lipid Abnormalities Are Associated with Adhesive Capsulitis Accompanied by Diabetes?

BACKGROUND

Adhesive capsulitis is common and can cause stiffness and pain. Diabetes and dyslipidemia are known to be associated with adhesive capsulitis. However, there is no report of any association between serum lipid profiles and adhesive capsulitis accompanied by diabetes.

QUESTION/PURPOSE

Which serum lipid abnormalities are associated with adhesive capsulitis accompanied by diabetes?

METHODS

This is a case-control study with two control groups. Our case group included 37 patients with newly diagnosed adhesive capsulitis accompanied by newly diagnosed diabetes who had no other diagnosed systemic diseases or rotator cuff tears. The two control groups each had 111 age- and sex-matched individuals with normal shoulder function (bilaterally pain-free, with full range of motion and no shoulder muscle weakness), no thyroid dysfunction, and no previously diagnosed systemic diseases. Individuals in the first control group had neither adhesive capsulitis nor diabetes. Individuals in the second control group had newly diagnosed diabetes without adhesive capsulitis. We evaluated any association between adhesive capsulitis accompanied by diabetes and serum lipid profile, including total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, and nonhigh-density lipoprotein (nonHDL). Conditional logistic regression analysis was used to evaluate the strengths of associations between serum lipid levels and adhesive capsulitis accompanied by diabetes, as determined by odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Low-density lipoprotein and nonHDL were associated with adhesive capsulitis accompanied by diabetes. Specifically, patients with adhesive capsulitis and diabetes had greater odds ratios of hyperlow-density lipoproteinemia when compared with individuals with neither adhesive capsulitis nor diabetes (OR, 3.19; 95% CI, 1.21-8.38; p = 0.019) and when compared with individuals without adhesive capsulitis but with newly diagnosed diabetes (OR, 5.76; 95% CI, 1.67-19.83; p = 0.005). Similarly, patients with adhesive capsulitis accompanied by diabetes had greater odds ratios of hypernonhigh-density lipoproteinemia when compared with individuals with neither adhesive capsulitis nor diabetes (OR, 7.39; 95% CI, 2.72-20.09; p < 0.001) and when compared with individuals without adhesive capsulitis but with newly diagnosed diabetes (OR, 3.26; 95% CI, 1.40-7.61; p = 0.006).

CONCLUSIONS

Inflammatory lipoproteinemias, particularly hyperlow-density lipoproteinemia and hypernonhigh-density lipoproteinemia, are associated with adhesive capsulitis accompanied by diabetes. Further research is needed to evaluate whether inflammatory lipoproteinemias are a cause, a related cofactor, or an aggravating factor in the development of adhesive capsulitis in people who have diabetes.

LEVEL OF EVIDENCE

Level III, prognostic study.

Low-density lipoprotein-associated variables and the severity of coronary artery disease: an untreated Chinese cohort study

BACKGROUND AND AIMS

Elevated low-density lipoprotein cholesterol (LDL-C) is causal risk for coronary artery disease (CAD) and LDL-associated variables including LDL-C, apolipoprotein B (apoB), non-high-density lipoprotein cholesterol (non-HDL-C), lipoprotein a [Lp(a)], small dense LDL (sd-LDL), and oxidized LDL (ox-LDL) have been widely used for predicting the risk of CAD. This study was aimed to compare the values of six LDL-related variables for predicting the severity of CAD using untreated patients undergoing coronary angiography (CAG).

METHODS

A group of 1977 individuals were consecutively enrolled and divided into CAD (n = 1151) and non-CAD groups (n = 826) according to the results of CAG. LDL-C, apoB, non-HDL-C, Lp(a), sd-LDL and ox-LDL were measured, respectively. The numbers of stenotic arteries and Gensini Scores (GS) were used to calculate the severity of CAD and the associations of six variables with the severity of CAD and predicting value of these parameters were simultaneously examined.

RESULTS

CAD patients had significantly higher concentrations of LDL-related variables than non-CAD ones (all p < 0.05). Importantly, all variables rose with the increase in the severity of CAD. The predicting value of CAD manifested as sd-LDL > ox-LDL > apoB > non-HDL-C > LDL-C > Lp(a) [area under curve (AUC): sd-LDL 0.641; ox-LDL 0.640; apoB 0.611; non-HDL-C 0.587; LDL-C 0.583; Lp(a) 0.554; respectively]. In multivariate logistic analysis, all variables showed as independent risk factors for the severity of CAD [odds ratio (OR): ox-LDL > sd-LDL > apoB > non-HDL-C > LDL-C > Lp(a)].

CONCLUSIONS

All of LDL-related variables could be useful marker for predicting the severity of CAD but sd-LDL and ox-LDL appeared to litter better. Further study may be needed to validate our results.

Discordance between lipoprotein particle number and cholesterol content: an update

PURPOSE OF REVIEW

The cholesterol content within atherogenic apolipoprotein-B (apoB) containing lipid particles is the center of consensus guidelines and clinicians' focus whenever evaluating a patient's risk for atherosclerotic cardiovascular disease. The pathobiology of atherosclerosis requires the retention of lipoprotein particles within the vascular intima over time followed by maladaptive inflammation resulting in plaque formation and rupture in some. The cholesterol content is widely variable within each particle creating either cholesterol-deplete or cholesterol-enriched particles. This variance in particle cholesterol content varies within and between individuals. Discordance analysis exploits this difference in cholesterol content of particles to demonstrate the differential significance of LDL-cholesterol (LDL-C) and non-HDL-C from measures of lipoprotein particle number in terms of assessing atherosclerotic cardiovascular disease risks.

RECENT FINDINGS

Three studies have added to the growing body of literature of discordance analysis. Despite wide variability of discordance cutoffs, baseline risk of atherosclerotic disease, and populations sampled, the conclusion remains the same: risk of atherosclerotic disease follows apoB lipid particle concentration rather than cholesterol content of lipid particles.

SUMMARY

In addition to traditional lipid fractions, assessments of atherogenic particle number should be strongly considered whenever assessing CVD risk in nontreated and treated individuals. There is a need for clinical trials that focus not only on the reduction in LDL-C but apoB, as well.

Update on the laboratory investigation of dyslipidemias

The role of the clinical laboratory is evolving to provide more information to clinicians to assess cardiovascular disease (CVD) risk and target therapy more effectively. Current routine methods to measure LDL-cholesterol (LDL-C), the Friedewald calculation, ultracentrifugation, electrophoresis and homogeneous direct methods have established limitations. Studies suggest that LDL and HDL size or particle concentration are alternative methods to predict future CVD risk. At this time there is no consensus role for lipoprotein particle or subclasses in CVD risk assessment. LDL and HDL particle concentration are measured by several methods, namely gradient gel electrophoresis, ultracentrifugation-vertical auto profile, nuclear magnetic resonance and ion mobility. It has been suggested that HDL functional assays may be better predictors of CVD risk. To assess the issue of lipoprotein subclasses/particles and HDL function as potential CVD risk markers robust, simple, validated analytical methods are required. In patients with small dense LDL particles, even a perfect measure of LDL-C will not reflect LDL particle concentration. Non-HDL-C is an alternative measurement and includes VLDL and CM remnant cholesterol and LDL-C. However, apolipoprotein B measurement may more accurately reflect LDL particle numbers. Non-fasting lipid measurements have many practical advantages. Defining thresholds for treatment with new measurements of CVD risk remain a challenge. In families with genetic variants, ApoCIII and lipoprotein (a) may be additional risk factors. Recognition of familial causes of dyslipidemias and diagnosis in childhood will result in early treatment. This review discusses the limitations in current laboratory technologies to predict CVD risk and reviews the evidence for emergent approaches using newer biomarkers in clinical practice.

The Ratio of Eicosapentaenoic Acid (EPA) to Arachidonic Acid may be a Residual Risk Marker in Stable Coronary Artery Disease Patients Receiving Treatment with Statin Following EPA Therapy

BACKGROUND

We investigated the relationship between the eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio and non-high-density lipoprotein cholesterol (non-HDL-C) level, a major residual risk of coronary artery disease (CAD), in statin-treated CAD patients following EPA therapy.

METHODS

We conducted a 6-month, prospective, randomized clinical trial to investigate the effect of the additional administration of EPA on the EPA/AA ratio and the serum non-HDL-C level in stable CAD patients receiving statin treatment. We assigned CAD patients already receiving statin therapy to an EPA group (1800 mg/day; n = 50) or a control group (n = 50).

RESULTS

A significant reduction in the serum non-HDL-C level was observed in the EPA group, compared with the control group (-9.7 vs. -1.2%, p = 0.01). A multiple-regression analysis with adjustments for coronary risk factors revealed that achieved EPA/AA ratio was more reliable as an independent and significant predictor of a reduction in the non-HDL-C level at a 6-month follow-up examination (β = -0.324, p = 0.033) than the absolute change in the EPA/AA ratio. Interestingly, significant negative correlations were found between the baseline levels and the absolute change values of both non-HDL-C and triglyceride-rich lipoproteins, both markers of residual risk of CAD, indicating that patients with a higher baseline residual risk achieved a greater reduction.

CONCLUSION

The present results suggest that the achieved EPA/AA ratio, but not the absolute change in EPA/AA ratio, following EPA therapy might be a useful marker for the risk stratification of CAD among statin-treated patients with a high non-HDL-C level.

CLINICAL TRIAL REGISTRATION

UMIN ( http://www.umin.ac.jp/ ) Study ID: UMIN000010452.

Association between discordance of LDL-C and non-HDL-C and clinical outcomes in patients with stent implantation: from the FU-Registry

It is not yet clear whether the discordance of low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) predicts the follow-up clinical outcome (major adverse cardiovascular events: MACEs) in patients with coronary stent implantation. Among 2015 patients with coronary stent implantation (Fukuoka University [FU]-Registry), excluding those with acute coronary syndrome or hemodialysis, we selected 801 patients who had undergone successful stent implantation with a follow-up until 18 months, and classified them into 3 groups according to baseline LDL-C and non-HDL-C levels [percentile(P)non-HDL-C more than (P)LDL-C, (P)non-HDL-C equal to (P)LDL-C, and (P)non-HDL-C less than (P) LDL-C]. We found that the discordance of (P)LDL-C and (P)non-HDL-C was not a significant predictor of MACEs. Higher LDL-C level was consistently and independently associated with higher incidences of MACEs after controlling for conventional risk factors and the type of stent used by multivariate Cox regression analyses. In conclusion, LDL-C levels are more important than non-HDL-C levels and the discordance of LDL-C and non-HDL-C levels as predictors of MACEs in patients with stable angina after stent implantation.

Glucose-independent association of adiposity and diet composition with cardiovascular risk in children and adolescents with type 1 diabetes

AIMS

To test the hypothesis that diet composition, adiposity and glycometabolic control could independently contribute to an increase in the cardiovascular risk (CVR) for children/adolescents with type 1 diabetes (T1D).

METHODS

One hundred and eighty children/adolescents with T1D (age range 5-18 years) were enrolled. Diet (3-day weighed dietary record), physical (height, weight, waist circumference, bioelectrical impedance analysis) and biochemical (HbA1c, lipid profile) parameters were recorded. Regression models, using non-HDL cholesterol (a gross index of CVR) as the dependent variable and HbA1c (mmol/mol), fat mass (FM) %, lipid-to-carbohydrate intake ratio as independent ones, were calculated.

RESULTS

Non-HDL cholesterol was significantly associated with adiposity (FM%; r = 0.27, 95% CI 0.13-0.43), body fat distribution (waist-to-height ratio; r = 0.16, 95% CI 0.02-0.31), lipid intake [% of energy intake (EI)] (r = 0.25, 95% CI 0.11-0.41), carbohydrate intake (% EI; r = -0.24, 95% CI 0.10-0.40), lipid-to-carbohydrate intake ratio (r = 0.26, 95% CI 0.12-0.42) and blood glucose control (HbA1c; r = 0.24, 95% CI 0.10-0.40). A p value cutoff of 0.10 was used for covariates to be included in the regression analysis. Multiple regression analysis showed that adiposity (FM%), blood glucose control (HbA1c) and lipid-to-carbohydrate intake ratio independently contributed to explaining the inter-individual variability of non-HDL cholesterol (R ² = 0.163, p < 0.05).

CONCLUSIONS

Adiposity and lipid-to-carbohydrate intake ratio affect non-HDL cholesterol, a gross index of CVR, regardless of HbA1c, in children and adolescents with T1D. Intervention to reduce CVR in T1D patients should focus not only on glycometabolic control but also on adiposity and diet composition.

Concerns About the Use of Non-High-Density Lipoprotein Cholesterol as a Lipid Predictor

Introduction: Non-high-density lipoprotein (non-HDL) cholesterol is the sum of low-density lipoprotein (LDL) cholesterol and very-low-density lipoprotein (VLDL) cholesterol, and is usually approximated by the total cholesterol minus HDL-cholesterol. The National Lipid Association (NLA) has advocated the use of non-HDL cholesterol as its favoured lipid predictor. Cut-off points are based on LDL cholesterol values, with a lower end at 100 mg/dL (2.50 mmol/L) and a higher end at 190 mg/dL (4.75 mmol/L), adding 30 mg/dL (0.75 mmol/L) to keep triglyceride (TG) levels <150 mg/dL (1.70 mmol/L). Objectives: The author will demonstrate that the use of non-HDL cholesterol has not been fully considered. Methods: The author will examine a general population lipid database to demonstrate the frequency of distribution of non-HDL cholesterol in the part of the population that was known to have developed a form of atherothrombotic disease (ATD) and in the part that was not known to have done so. The effect of stratifying each non-HDL cholesterol quintile in terms of another lipid predictor that does not involve VLDL-cholesterol or TG will be demonstrated. The other risk predictor is the cholesterol retention fraction (CRF) defined as (LDL-HDL)/LDL. Findings: All non-HDL cholesterol quintiles above the lowest quintile had higher frequencies in the ATD population than in the non-ATD population. The highest two quintiles had frequencies in the ATD population that are 2.5-times as high as those in the non-ATD population, whereas in the middle two quintiles, the frequency in the ATD population was minimally higher than in the non-ATD population. In the lowest quintile, the frequency is much higher in the non-ATD population than in the ATD population. At any non-HDL cholesterol quintile, the average age of ATD onset depends on cigarette smoking (not discussed here) and the CRF. Higher CRF levels equate to an earlier average age of ATD onset and lower levels of CRF equate to a later onset. A 75-year-old male who was a hypertensive diabetic and a former smoker was not on statins because of low lipid levels, had clean arteries on angiography, whereas a 45-year-old normotensive, non-smoking patient with severe dyslipidaemia (obtained at first encounter) had a massive stroke due to carotid stenosis. Both had non-HDL cholesterol levels in the intermediate ATD risk quintiles. Conclusions: Non-HDL cholesterol is not the optimal predictor of the population at risk of atherothrombotic disease and its use should be reconsidered.

Apolipoprotein B vs non-high-density lipoprotein cholesterol: Association with endothelial hemostatic markers and carotid intima-media thickness

BACKGROUND

Both apolipoprotein B (apoB) and non-high-density lipoprotein cholesterol (non-HDL-C) are accepted as alternative risk factors or targets for lipid-lowering therapy, which correlate more strongly with cardiovascular events than low-density lipoprotein cholesterol.

OBJECTIVE

The aim of this cross-sectional study was to evaluate the differences in plasma levels of plasminogen activator inhibitor-1 (PAI-1) and of von Willebrand factor (vWF) as endothelial hemostatic markers and carotid intima-media thickness (C-IMT) as a morphologic marker for atherosclerotic vascular disease among dyslipidemic individuals with apoB levels higher, estimated or lower based on regression equation of apoB vs non-HDL-C.

METHODS

A total of 594 dyslipidemic subjects without atherosclerotic manifestation were divided into 3 groups (according to tertiles of apoB levels above, within, and below the line of identity): H-apoB (n = 200), E-apoB (n = 194), and L-apoB (n = 200). PAI-1, vWF, C-IMT and lipids, anthropometric parameters, markers of insulin resistance, and inflammation were measured. Differences in variables between groups were analyzed using analysis of variance.

RESULTS

There was a strong association between apoB and non-HDL-C. The correlations of apoB and of non-HDL-C with markers of endothelial damage and C-IMT were very similar. Despite these facts, individuals with higher apoB levels had significantly higher levels of PAI-1 compared with individuals with estimated (P < .05) or lower apoB (P < .001). There were no significant differences in vWF, C-IMT, markers of insulin resistance, obesity, and inflammation.

CONCLUSION

Individuals with apoB higher than predicted by non-HDL-C had significantly higher levels of PAI-1, which may contribute to the increased risk of future atherothrombotic events.

Plasma proprotein convertase subtilisin/kexin type 9 is associated with Lp(a) in type 2 diabetic patients

AIM

Recent in vitro researches have shown that plasma Lp(a) can be reduced using a proprotein convertase subtilisin/kexin type 9 (PCSK9)-inhibitory monoclonal antibody. In our clinical study we tried to investigate the association between plasma Lp(a) and PCSK9 in Type 2 diabetic patients with elevated plasma Lp(a), and to check whether such an association would be related to LDL-receptor (LDL-R) levels.

METHODS

Plasma PCSK9 and LDL-R concentrations were measured by sandwich ELISA methods using recombinant human PCSK9 protein and LDL-R protein as standards in a cohort with type 2 diabetic patients (n=50) compared to an age- and sex-matched control group (n=50). Both clinical and biochemical parameters were determined in all patients.

RESULTS

Plasma PCSK9 level was significantly elevated in T2DM patients compared to controls (44.61±14.44 and 33.22±11.79ng/mL, respectively, P<0.0001). However LDL-R levels did not differ between the two groups. Remarkably, plasma PCSK9 levels were positively correlated with Lp(a) levels in whole population (r=+0.227, P=0.03) as well as in T2DM group (r=+0.398, P=0.0061) but not in control group. Multiple linear regression analysis showed that plasma Lp(a) levels were independently associated to those of PCSK9.

CONCLUSION

Lp(a) has been proposed as a contributing factor to the accelerated development of macrovascular complications in T2DM. Its synergic effect with PCSK9 may explain the enhanced atherogenicity in T2DM patients.

JTT-130, a novel intestine-specific inhibitor of microsomal triglyceride transfer protein, ameliorates lipid metabolism and attenuates atherosclerosis in hyperlipidemic animal models

JTT-130 was developed as an intestine-specific MTP inhibitor designed to rapidly catabolize after absorption to avoid causing hepatotoxicity due to hepatic MTP inhibition. In previous reports, we have demonstrated that JTT-130 suppresses dietary lipid absorption in the small intestine without inducing hepatic steatosis. Thus, in this report, JTT-130 was administered to hyperlipidemic animals fed a Western diet to investigate the effect of intestinal MTP inhibition on lipid metabolism and progression of atherosclerosis. JTT-130 potently lowered plasma non-high density lipoprotein-cholesterol, and elevated plasma high density lipoprotein-cholesterol (HDL-C), indicating improvement in atherogenic index in hamsters. HDL fractions obtained after two weeks treatment with JTT-130 significantly increased the efflux of cholesterol from macrophages, as an index parameter of HDL function. Furthermore, long-term treatment with JTT-130 also improved the plasma lipid profile without inducing hepatic steatosis in rabbits, resulting in the suppression of atherosclerosis formation in aortas. From these results, JTT-130 ameliorates lipid metabolism accompanied with the enhancement of the anti-atherosclerotic function of HDL, and attenuates the progression of atherosclerosis in hyperlipidemic animals. These findings indicate that intestinal MTP inhibition may be atherogenic in vivo and that JTT-130 may be a useful compound for the treatment of dyslipidemia and a potential anti-atherogenic drug.

Circulating non-HDL-C levels were more relevant to atherogenic lipoprotein subfractions compared with LDL-C in patients with stable coronary artery disease

BACKGROUND

Conflicting results have been yielded as to whether low-density lipoprotein (LDL) cholesterol (LDL-C) or non-high-density lipoprotein (HDL) cholesterol (non-HDL-C) is a better marker of coronary artery disease (CAD) risk. Recently, plasma LDL and HDL subfractions have been suggested to be more accurately reflecting the lipoproteins' atherogenicity.

OBJECTIVE

We sought to compare the relationship between LDL-C or non-HDL-C and lipoprotein subfractions.

METHODS

We conducted a cross-sectional study in 351 consecutive stable CAD patients without lipid-lowering therapy. The LDL and HDL separations were performed using the Lipoprint System. The LDL-C levels were measured directly, and the non-HDL-C levels were calculated.

RESULTS

The cholesterol concentrations of LDL (large, medium, and small) and HDL (small) particles were increased (all P < .001) by non-HDL-C or LDL-C quartiles, whereas the mean LDL particle size and cholesterol concentrations of HDL (large) were decreased (both P < .001) by non-HDL-C quartiles. In age- and gender-adjusted analysis, the cholesterol in small LDL was much strongly related to non-HDL-C than to LDL-C (r = 0.539 vs 0.397, both P < .001). Meanwhile, the mean LDL particle size was more closely associated with non-HDL-C than LDL-C (r = -0.336 vs r = -0.136, both P < .05). Significantly, the cholesterol in large HDL was negatively correlated with non-HDL-C (r = -0223, P < .001) but not with LDL-C. These correlations were further confirmed by the fully adjusted multivariable linear regression analysis.

CONCLUSIONS

Non-HDL-C, in comparison to LDL-C, was more relevant to atherogenic lipoprotein subfractions in patients with stable CAD, supporting that it may be better in assessing cardiovascular risk.

Clinical guidelines on hyperlipidaemia: recent developments, future challenges and the need for an Australian review

Large reductions in cardiovascular disease (CVD) mortality have been achieved over the last 50 years in developed countries. The health policies that have contributed so much to this success have largely been coordinated by means of expert guidelines for the management of the classic modifiable risk factors such as blood pressure, diabetes and blood lipids. National and international guidelines for lipid management have demonstrated a high degree of consistency between numerous sets of recommendations. It has been argued that some important components of the consensus that has been established over the past decade have been challenged by the latest guidelines of the American Heart Association - American College of Cardiologists (AHA-ACC). Clinicians can be reassured that continued reliance on extensive scientific evidence has reaffirmed the importance of lipid metabolism as a modifiable risk factor for atherosclerotic cardiovascular disease. On the other hand, the recent AHA-ACC guidelines suggest changes in the strategies by which metabolic risk factors may be modified. This small number of important changes should not be sensationalised because these differences usefully reflect the need for guidelines to evolve to accommodate different contexts and changing perspectives as well as emerging issues and new information for which clinical trial evidence is incomplete. This article will consider the recent policies and responses of national and supranational organisations on topics including components of CVD risk assessment, sources of CVD risk information and re-appraisal of lipid-lowering interventions. Timely review of Australian lipid management guidelines will require consideration of these issues because they are creating a new context within which new guidelines must evolve.

Smoking and lipid-related indices in patients with diabetes mellitus

AIMS

Lipid-related indices, including the ratio of LDL cholesterol to HDL cholesterol, the ratio of triglycerides to HDL cholesterol and lipid accumulation product, are known to be good discriminators for cardiovascular disease. The aim of this study was to clarify the relationships between smoking and the lipid indices in patients with diabetes.

METHODS

Subjects were those who had been diagnosed as having diabetes mellitus at annual health check-ups at their places of work (n = 2563). The subjects were divided into three groups of non-smokers, light smokers (≤ 20 cigarettes/day) and heavy smokers (> 20 cigarettes/day). The relationships between smoking and the lipid indices were investigated.

RESULTS

Both in all subjects and in the subjects without a habit of alcohol drinking, the LDL cholesterol:HDL cholesterol ratio and the log-transformed triglyerides:HDL cholesterol ratio tended to be higher with an increase in the amount of smoking, and the log-transformed lipid accumulation product was significantly higher in heavy smokers than in non-smokers. In the non-alcohol drinking subjects, the odds ratios of heavy smokers vs. non-smokers for high LDL cholesterol:HDL cholesterol ratio [2.32 (95% CI 1.40-3.84)], for high triglycerides:HDL cholesterol ratio [1.69 (95% CI 1.06-2.69)] and for high lipid accumulation product [1.65 (95% CI 1.02-2.67)] were significantly higher than a reference level of 1.00. The associations between smoking and the lipid indices were weaker in alcohol drinkers than in non-drinkers.

CONCLUSIONS

In patients with diabetes, the levels of lipid-related indices were higher in smokers than in non-smokers, and cardiometabolic disorders, reflected by high lipid indices, are thought to be involved in the proneness of smokers to develop atherosclerotic cardiovascular disease.

A reappraisal of the risks and benefits of treating to target with cholesterol lowering drugs

Atherosclerotic cardiovascular disease (CVD) is the number one cause of death globally, and lipid modification, particularly lowering of low density lipoprotein cholesterol (LDLc), is one of the cornerstones of prevention and treatment. However, even after lowering of LDLc to conventional goals, a sizeable number of patients continue to suffer cardiovascular events. More aggressive lowering of LDLc and optimization of other lipid parameters like triglycerides (TG) and high density lipoprotein cholesterol (HDLc) have been proposed as two potential strategies to address this residual risk. These strategies entail use of maximal doses of highly potent HMG CoA reductase inhibitors (statins) and combination therapy with other lipid modifying agents. Though statins in general are fairly well tolerated, adverse events like myopathy are dose related. There are further risks with combination therapy. In this article, we review the adverse effects of lipid modifying agents used alone and in combination and weigh these effects against the evidence demonstrating their efficacy in reducing cardiovascular events, cardiovascular mortality, and all cause mortality. For patients with established CVD, statins are the only group of drugs that have shown consistent reductions in hard outcomes. Though more aggressive lipid lowering with high dose potent statins can reduce rates of non fatal events and need for interventions, the incremental mortality benefits remain unclear, and their use is associated with a higher rate of drug related adverse effects. Myopathy and renal events have been a significant concern with the use of high potency statin drugs, in particular simvastatin and rosuvastatin. For patients who have not reached target LDL levels or have residual lipid abnormalities on maximal doses of statins, the addition of other agents has not been shown to improve clinical outcomes and carries an increased risk of adverse events. The clinical benefits of drugs to raise HDLc remain unproven. In patients without known cardiovascular disease, there is conflicting evidence as to the benefits of aggressive pursuit of numerical lipid targets, particularly with respect to all cause mortality. Certainly, in statin intolerant patients, alternative agents with a low side effect profile are desirable. Bile acid sequestrants are an effective and safe choice for decreasing LDLc, and omega-3 fatty acids are safe agents to decrease TG. There remains an obvious need to design and carry out large scale studies to help determine which agents, when combined with statins, have the greatest benefit on cardiovascular disease with the least added risk. These studies should be designed to assess the impact on clinical outcomes rather than surrogate endpoints, and require a comprehensive assessment and reporting of safety outcomes.

Dysmetabolic signals in "metabolically healthy" obesity

SUMMARY

BACKGROUND

Obesity is associated with decreased insulin sensitivity, atherogenic dyslipidemia and hypertension, but clinical studies have also identified a "metabolically healthy" obese phenotype.

OBJECTIVE

To compare the characteristics of so-called "metabolically healthy" obese (MHO), normal weight subjects (MHNW) and obese with insulin resistance in the United States National Health and Nutrition Examination Survey, 1999-2004 (NHANES).

DESIGN, SETTING AND PARTICIPANTS

Insulin resistance was defined by a homeostatic model assessment (HOMA) value in the upper tertile for the entire NHANES cohort. "Metabolic health" was defined as the absence of diabetes, insulin resistance, metabolic syndrome, and lipid-lowering therapy. The study evaluated the 314 MHO, 1173 MHNW and 843 insulin-resistant obese from among the 6485 non-diabetic, non-pregnant adults aged 20-79 years.

MAIN OUTCOME MEASURES

Demographic, metabolic, nutrition and physical activity features.

RESULTS

MHO and MHNW groups were similar regarding age, and fasting glucose and triglyceride levels. MHO had higher insulin (P < 0.0001), insulin resistance as measured with the homeostatic model (P < 0.0001), non-HDL cholesterol (P = 0.002 in females and P = 0.049 in males) and C-reactive protein levels (P < 0.0001 in females and P = 0.038 in males), and lower high-density lipoprotein cholesterol (HDL) levels (P < 0.002). In addition, MHO females had higher low-density lipoprotein (LDL) cholesterol levels (P = 0.012) and systolic blood pressure (P = 0.02), and lower intake of dietary fiber (P = 0.0009) and levels of physical activity (P = 0.002). Triglycerides levels were normal in the MHO group.

CONCLUSIONS

"Metabolically healthy" obese people have multiple dysmetabolic changes that may signal increased risk for coronary artery disease.

Non-HDL-cholesterol in an adolescent diabetes population

BACKGROUND

Screening for dyslipidemia poses some challenges. Nonfasting lipid profiles frequently have elevated triglycerides. In addition, in the standard lipid profile, low-density lipoprotein (LDL) cholesterol is a calculated value rather than a direct measurement and is triglyceride dependent. Non-high-density lipoprotein cholesterol (non-HDL-C) is an alternative method to assess for dyslipidemia and provides a single estimate of all atherogenic apolipoprotein B-containing lipoproteins.

OBJECTIVE

To calculate the non-HDL-C in adolescents with diabetes and to evaluate risk factors associated with an elevated non-HDL-C and to compare the prevalence of dyslipidemia, defined by non-HDL-C, with the prevalence of dyslipidemia defined by LDL cholesterol in the SEARCH study.

METHODS

Data were collected from 502 adolescent patients with diabetes and analyzed. Non-HDL-C was calculated and levels were categorized into normal, borderline, and high based on the National Cholesterol Education Program.

RESULTS

Lipid profile was performed in 370 patients, 92% of whom had type 1 diabetes. In the 339 subjects with type 1 diabetes, mean hemoglobin A1c (HbA1c) of those with normal non-HDL-C (8.6%) was significantly lower than the HbA1c of those with high non-HDL-C (9.6%) (P = .005). Subjects with normal non-HDL-C had a lower body mass index (BMI) z-score (0.4 ± 0.8) than the group with borderline and high non-HDL-C (0.75 ± 0.9%), P = .002. In the 31 subjects with type 2 diabetes, the mean HbA1c of those with normal non-HDL-C (8.1%) and those with borderline non-HDL-C (7.0%) was significantly lower than the mean HbA1c of those with high non-HDL-C (11.8%) (P = .04, and P = .009, respectively). In addition, the subjects with normal non-HDL-C had a lower BMI z-score (1.3 ± 1.3) than the group with borderline and high non-HDL-C (2.2 ± 0.6%), P = .03. The prevalence of dyslipidemia using non-HDL-C was similar to prevalence rates using LDL-C in the SEARCH study.

CONCLUSIONS

In adolescents with diabetes, non-HDL-C is increased with poorer diabetes control and higher BMI. It appears to be a superior nonfasting lipid screening test for adolescents with diabetes that can be readily calculated on a randomly obtained rather than fasting sample.

Is the superiority of apoB over non-HDL-C as a marker of cardiovascular risk in the INTERHEART study due to confounding by related variables?

BACKGROUND

Patients with increased numbers of cholesterol-depleted apolipoprotein B (apoB) particles frequently have multiple other abnormalities, which might confound the comparison of apoB and non-high-density-lipoprotein-cholesterol (non-HDL-C) as markers of cardiovascular risk.

OBJECTIVE

We wanted to determine whether the superiority of apoB over non-HDL-C as a marker of cardiovascular risk in the INTERHEART study is due to such variables that act as confounders of the primary comparison.

METHODS

To test for confounding, cases and controls were first separated into 3 groups on the basis of the percentile levels within the study of non-HDL-C and apoB with discordance defined as a difference of 5 percentile points. Logistic regression was used to compute odds ratio of myocardial infarction (as an outcome) for different categories, assuming concordance as reference adjusted for other confounders.

RESULTS

Plasma triglyceride and non-HDL-C levels were highest in the discordant group with lowest risk and lowest in the discordant group with highest risk, whereas apoB was highest in the discordant group with the highest risk and lowest in the discordant group with the lowest group. Moreover, no significant change was found in the odds ratio for either discordant group when adjusted for the effect of any of the variables examined, evidence that none confounded the primary comparison.

CONCLUSION

Factors such as hypertriglyceridemia do not confound the comparison of apoB and non-HDL-C, further evidence that apoB is superior to non-HDL-C as a marker of the importance of the apoB atherogenic lipoproteins in cardiovascular risk.

Is the future of statins aligned with new novel lipid modulation therapies?

Dyslipidemia is an established risk factor for the development of atherosclerotic cardiovascular disease. Statin therapy has been proven in a number of clinical trials to lower the risk of acute cardiovascular events and is the mainstay of cholesterol treatment. Despite current optimal treatment for dyslipidemia, many patients fail to reach adequate cholesterol treatment goals and remain at a significantly increased risk of cardiovascular events. Given this residual risk, there is a critical need for additional lipid therapies that could augment the ability of statins to lower the burden of atherogenic lipoproteins and, in some cases, raise levels of high-density lipoproteins. A number of novel lipid-altering therapies have been developed and are currently in clinical trials. In this review, we discuss these promising therapies, which include PCSK9 inhibitors, apolipoprotein B antisense oligonucleotides, microsomal transfer protein inhibitors, thyroid mimetics, and cholesteryl ester transfer protein inhibitors. Although statin therapy is the current recommended primary treatment for dyslipidemia, emerging novel agents may become adjuvant therapies in the treatment of atherosclerotic heart disease.

A new ratio for better predicting future death/myocardial infarction than standard lipid measurements in women >50 years undergoing coronary angiography: the apolipoprotein A1 remnant ratio (Apo A1/ [VLDL₃+IDL])

BACKGROUND

Women often lag behind men in their risk of cardiovascular events. However, with age and the onset of menopause, women's cardiovascular risk eventually becomes similar to that of men. This change in risk may, in part, be attributable to a shift to a more atherogenic lipid profile. Our objective was to evaluate standard- and sub-lipid parameters and the apo A1 remnant ratio: (apo A1/[VLDL₃-C+IDL-C]) for their associations with death/myocardial infarction among peri- and post-menopausal women.

METHODS

Women (N=711) >50 years of age undergoing coronary angiography were evaluated. Baseline clinical and angiographic characteristics, lipids, and sub-lipid levels (Vertical Auto Profile method) were collected. Cox regression analysis, adjusted by standard cardiovascular risk factors, was utilized to determine associations of lipid and sub-lipid tertiles(T) with death/myocardial infarction at 1 and 3 years.

RESULTS

Patients averaged 67.7±9.4 years and 53.6% had underlying severe (≥70% stenosis) coronary artery disease. The apo A1 remnant ratio was found to have stronger associations for 1 year (T1 vs. T3: HR=2.13, p=0.03, T2 vs. T3: HR=1.57, p=0.21) and 3 year (T1 vs. T3: HR=2.32, p=0.002, T2 vs. T3: HR=1.97, p=0.01) death/myocardial infarction than any individual lipid (LDL-C, HDL-C, triglycerides, non-HDL-C) or sub-lipid (apo A1, apo B, VLDL₃-C+IDL-C) measure, or any other well-known ratio (triglyercies/HDL-C, apo B/A1, TChol/HDL-C, HDL-C/[VLDL₃-C+IDL-C]).

CONCLUSIONS

The apo A1 remnant ratio was a significant predictor of short and intermediate-term death/myocardial infarction risk among women >50 years of age. Furthermore, this ratio was found to have greater predictive ability than traditional lipid and sub-lipid parameters and represents a potential new risk marker.

Association of apolipoprotein B and nuclear magnetic resonance spectroscopy-derived LDL particle number with outcomes in 25 clinical studies: assessment by the AACC Lipoprotein and Vascular Diseases Division Working Group on Best Practices

BACKGROUND

The number of circulating LDL particles is a strong indicator of future cardiovascular disease (CVD) events, even superior to the concentration of LDL cholesterol. Atherogenic (primarily LDL) particle number is typically determined either directly by the serum concentration of apolipoprotein B (apo B) or indirectly by nuclear magnetic resonance (NMR) spectroscopy of serum to obtain NMR-derived LDL particle number (LDL-P).

CONTENT

To assess the comparability of apo B and LDL-P, we reviewed 25 clinical studies containing 85 outcomes for which both biomarkers were determined. In 21 of 25 (84.0%) studies, both apo B and LDL-P were significant for at least 1 outcome. Neither was significant for any outcome in only 1 study (4.0%). In 50 of 85 comparisons (58.8%), both apo B and LDL-P had statistically significant associations with the clinical outcome, whereas in 17 comparisons (20.0%) neither was significantly associated with the outcome. In 18 comparisons (21.1%) there was discordance between apo B and LDL-P.

CONCLUSIONS

In most studies, both apo B and LDL-P were comparable in association with clinical outcomes. The biomarkers were nearly equivalent in their ability to assess risk for CVD and both have consistently been shown to be stronger risk factors than LDL-C. We support the adoption of apo B and/or LDL-P as indicators of atherogenic particle numbers into CVD risk screening and treatment guidelines. Currently, in the opinion of this Working Group on Best Practices, apo B appears to be the preferable biomarker for guideline adoption because of its availability, scalability, standardization, and relatively low cost.

Establishing cut-off values for apolipoprotein B and non-HDL-C according to LDL-C values in a South European population

BACKGROUND

Low-density lipoprotein cholesterol (LDL-C) remains the primary target of therapy in most strategies of dyslipidaemia management focused on cardiovascular disease prevention. Different guidelines have identified specific LDL-C cut-off points as targets for therapeutic intervention. Many clinical situations characterised by dyslipidaemia and elevated triglycerides are common in our environment and in overall industrialised countries. Thus, lipid goals based only on LDL-C could misclassify an important percentage of subjects. The objective of the present study was to establish cut-off point values for apoB and non-HDL-C in relation to the identified LDL-C cut-off points for cardiovascular risk in a South European population.

METHODS

We performed a cross-sectional study including 1501 subjects (770 women and 731 men) between 18 and 80 years of age. Samples were collected after 12-14 h of fasting. Cholesterol, HDL-C, triglycerides and apoB levels were measured using direct methods. LDL-C was calculated by the Friedewald formula. Non-HDL-C was calculated as total cholesterol minus HDL-C.

RESULTS

The Spearman's rank correlations between apoB and LDL-C (r 0.86, p < 0.0001), and between apoB and non-HDL-C (r 0.91, p < 0.0001) were both significant. The proposed cut-off points for apoB, according to LDL-C goals (70, 100, 130 and 160 mg/dl) in our population are 70, 80, 100 and 115 mg/dl respectively. The proposed cut-off values for non-HDL-C are 100, 120, 150 and 190 mg/dl respectively.

CONCLUSION

The established LDL-C cut-off values could not be accurate to estimate cardiovascular risk in subjects with mild hypertriglyceridaemia, as frequently occurs in our Mediterranean population. To take into consideration the burden of atherogenic particles and better classify patients at risk we propose cut-off values for apoB or the equivalent for non-HDL-C. Prospective trials including cardiovascular variables are needed to validate our assumption.

Food prices and blood cholesterol

Cardiovascular diseases (CVD) cost Americans billions of dollars per year. High cholesterol levels, which are closely related to dietary habits, are a major contributor to CVD. In this article, we study whether changes in food prices are related to cholesterol levels and whether taxes or subsidies on particular foods would be effective in lowering cholesterol levels and, consequently, CVD costs. We find that prices of vegetables, processed foods, whole milk and whole grains are significantly associated with blood cholesterol levels. Having analyzed the costs and benefits of government interventions, we find that a subsidy of vegetables and whole grains would be an efficient way to reduce CVD expenditures.

Discordance analysis of apolipoprotein B and non-high density lipoprotein cholesterol as markers of cardiovascular risk in the INTERHEART study

OBJECTIVES

Whether non-HDL-C and apoB are equivalent markers of cardiovascular risk remains controversial. Only when apoB particles in toto contain either more or less cholesterol than normal - that is, when their composition is discordant - could apoB and non-HDL-C predict risk differently. Accordingly, this study tests within the INTERHEART data base whether apoB or non-HDL-C are equivalent markers of risk when the two markers are discordant.

METHODS

The INTERHEART study is a standardized case-control study of acute myocardial infarction with blood samples in 9345 cases and 12,120 controls from 52 countries. To produce comparability, the concentrations of non-HDL-C and apoB are expressed as percentiles (P) within the study population. Concordance is defined as the phenotype when P Non-HDL-C = P apoB (that is, apoB particles contain a normal mass of cholesterol). Discordance is defined either as the phenotype when P Non-HDL-C > P apoB (cholesterol-enriched apoB particles) or P Non-HDL-C < P apoB (cholesterol-depleted apoB particles). The OR of cases to controls was determined for both discordant groups and compared to the ratio of cases to controls in the concordant group, which was the reference group. An OR > 1 means that risk is greater in the discordant than in the reference phenotype whereas an OR < 1 means the cases are less common in the discordant phenotype than in the reference group.

RESULTS

When discordance was defined as percentiles within 5%, a definition that produced equal numbers of discordant and concordant individuals, the OR for P Non-HDL-C > apoB (cholesterol-enriched apoB particles) was 0.72 (0.67-0.77 95% CI) indicating risk was less than the reference concordant group whereas the OR for P Non-HDL-C < apoB (cholesterol-depleted apoB particles) was 1.58 (1.38-1.58 95% CI) indicating risk was significantly greater than the reference concordant group. The same findings were reproduced using all definitions of discordance from 1% to 10%. Moreover, the pattern of findings was consistent amongst the ethnic groups that made up the overall study population.

CONCLUSION

Discordance analysis demonstrates that apoB is a more accurate marker of cardiovascular risk than non-HDL-C.

Utility of non-high-density lipoprotein cholesterol in assessing incident type 2 diabetes risk

AIMS

Traditional lipid indices have been associated with type 2 diabetes, but limited data are available regarding non-high-density lipoprotein (non-HDL) cholesterol. In view of recent guidelines for the clinical management of dyslipidemia recommending the monitoring of non-HDL cholesterol as a secondary target after achieving the low-density lipoprotein (LDL) cholesterol goal, we aimed to assess the association of non-HDL cholesterol with incident type 2 diabetes and compare its utility as a risk predictor with traditional lipid variables in Aboriginal Canadians.

METHODS

Of 606 diabetes-free participants at baseline, 540 (89.1%) returned for 10-year follow-up assessments. Baseline anthropometry, blood pressure, fasting insulin and serum lipids were measured. Fasting and 2-h postload glucose were obtained at baseline and follow-up to determine the incidence of type 2 diabetes.

RESULTS

The cumulative incidence of type 2 diabetes was 17.5%. Higher non-HDL cholesterol, total-to-HDL cholesterol ratio, apolipoprotein B, triglyceride and LDL cholesterol and lower HDL cholesterol concentrations were individually associated with incident type 2 diabetes in univariate analyses (all p < 0.05). Non-HDL cholesterol was a superior determinant of incident diabetes compared with LDL cholesterol (comparing C-statistics of univariate models p = 0.01) or HDL cholesterol (p = 0.004). With multivariate adjustment including waist circumference, non-HDL cholesterol remained associated with incident diabetes [odds ratio (OR) 1.42 (95% confidence interval, CI 1.07-1.88)], while LDL cholesterol and HDL cholesterol became non-significant.

CONCLUSIONS

Non-HDL cholesterol was associated with incident type 2 diabetes and was superior to LDL cholesterol as a risk predictor in this population. Further studies are required to establish the utility of non-HDL cholesterol in non-Aboriginal populations.

Pravastatin and fenofibrate in combination (Pravafenix(®)) for the treatment of high-risk patients with mixed hyperlipidemia

Pravafenix(®) is a fixed-dose combination of pravastatin 40 mg and fenofibrate 160 mg. The rationale for the use of Pravafenix is based on the increased residual cardiovascular risk observed for high-risk patients with either increased triglycerides or low HDL cholesterol levels despite statin monotherapy. This article reviews the current available information on the pharmacology, clinical efficacy and safety of Pravafenix. Pravafenix is recommended to be taken with food in the evening. In clinical trials, Pravafenix consistently produces complementary benefits on the overall atherogenic lipid profile of high-risk patients with mixed hyperlipidemia not controlled by either pravastatin 40 mg or simvastatin 20 mg. Within the limitations of the database, Pravafenix seems to be well tolerated up to 64 weeks, with an overall tolerability and safety profile consistent with findings generally observed with fenofibrate treatment. In particular, no myopathy or rhabdomyolysis has been reported. The actual European indication is restricted to high-risk patients with mixed hyperlipidemia whose LDL cholesterol levels are adequately controlled on pravastatin 40 mg monotherapy. Whether Pravafenix confers additional cardiovascular benefits in high-risk patients treated with a statin remains to be determined.

Comparison of various lipid variables as predictors of coronary heart disease in Japanese men and women with type 2 diabetes: subanalysis of the Japan Diabetes Complications Study

OBJECTIVE

To determine the best lipid variable to predict coronary heart disease (CHD) in Japanese patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Eligible Japanese men and women (1,771) aged 40-70 years with type 2 diabetes from 59 institutes nationwide were followed for a planned 8-year period. The performance of eight conventional lipid variables, i.e., total cholesterol (TC), LDL-cholesterol (LDLC), HDL-cholesterol (HDLC), triglycerides (TGs), non-HDLC, TC/HDLC ratio, LDLC/HDLC ratio, and TG/HDLC ratio, as predictors of incident CHD were evaluated by four methods: hazard ratio (HR) per one SD increment by multivariate Cox analysis, χ(2) likelihood ratio test, area under the receiver operating characteristic curve (AUC), and tertile analysis.

RESULTS

Although all variables significantly predicted CHD events in men, non-HDLC (HR per one SD 1.78 [95% CI 1.43-2.21]; AUC 0.726) and TC/HDLC (HR 1.63 [1.36-1.95]; AUC 0.718) had the better predictive performances among the variables, including LDLC. In women, TGs (log-transformed; HR 1.72 [1.21-2.43]; AUC 0.708) were the best predictor according to results of tertile analysis (HR of the top tertile versus the bottom tertile 4.31 [1.53-12.16]). The associations with incident CHD were linear and continuous.

CONCLUSIONS

For Japanese diabetic men, non-HDLC and TC/HDLC were the best predictors, whereas TGs were most predictive for women. These findings, which included prominent sex differences, should be considered among clinical approaches to risk reduction among East Asians with diabetes.

Treatment options for the management of hypertriglyceridemia: strategies based on the best-available evidence

A severe elevation in triglycerides (TG; ≥500 mg/dL) increases the risk for pancreatitis. TG levels ≥200 mg/dL are associated with a greater risk of atherosclerotic coronary heart disease (CHD). However, no outcomes trials exist to assess the efficacy of TG lowering for preventing pancreatitis in patients with severe hypertriglyceridemia. Similarly, no completed prospective outcomes trial exists to support or refute a reduction in CHD risk resulting from lipid-altering therapy in patients specifically selected for the presence of hypertriglyceridemia. This review examines the available evidence for the use of statins, omega-3 fatty acids, fibrates, and niacin in the management of hypertriglyceridemic patients. Results from CHD outcomes trials support statins as the first-line lipid-altering drug therapy to reduce CHD in hypercholesterolemic patients, and subgroup analyses suggest statins are efficacious in hypertriglyceridemic patients with fasting TG levels <500 mg/dL. Omega-3 fatty acids and fibrates are reasonable first drug options for patients with TG ≥500 mg/dL and often are used to lower TG levels with the objective of reducing pancreatitis risk, although a statin or niacin may also be reasonable options. Combination lipid drug therapy may be needed to achieve both low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol treatment goals for CHD prevention in patients with elevated TG levels, particularly those with TG ≥500 mg/dL. Additional clinical outcomes data are needed to provide a more evidence-based rationale for clinical lipid management of hypertriglyceridemic patients.