To B or not to B: is non-high-density lipoprotein cholesterol an adequate surrogate for apolipoprotein B?

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.

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.

Non-HDL as a Valid Surrogate Marker of Small Dense LDL in a Young Indian Population

Small dense (sd) LDL is a significant independent risk factor for premature coronary artery disease (CAD). Unfortunately, its estimation is not popular, due to the limited availability of specialized equipment, high cost and time-consuming technique. Non-HDL is a calculated, single index measure of all atherogenic apolipoprotein-B containing lipoproteins. This study aimed at identifying non-HDL as a superior surrogate marker of sdLDL cholesterol in a young Indian population. 161 healthy subjects < 45 years were tested for lipid profile, apolipoproteins A1 and B, and sdLDL particle size. sdLDL particles showed negative correlation with non-HDL (r = - 0.283, p < 0.001), LDL (r = - 0.195, p = 0.013) and apoB/apo A1 (r = - 0.175, p = 0.026), the significance being greatest with non-HDL. ROC showed AUC for non-HDL, LDL and apoB/apo A1 as 0.704, 0.686, and 0.596 respectively. For LDL < 130 mg/dL, sdLDL showed a more significant negative correlation with non-HDL (r = - 0.291, p < 0.001) as compared with apoB/apoA1 (r = - 0.172, p = 0.037). For triglycerides < 200 mg/dL, sdLDL particle size showed higher significant negative correlation with non-HDL (r = - 0.213, p = 0.015) than with LDL (r = - 0.176, p = 0.045) while for triglycerides between 200 and 400 mg/dL, significant negative correlation was observed only with non-HDL (r = - 0.372, p = 0.043). Hence, our study suggested that non-HDL is a superior surrogate marker of sdLDL particle size as compared to LDL and apoB/A1 ratio in a young healthy Indian population and should be used for optimum assessment of dyslipidemias and CAD risk.

Dapagliflozin in patients with type II diabetes mellitus, with and without elevated triglyceride and reduced high-density lipoprotein cholesterol levels

BACKGROUND

Dapagliflozin is a selective sodium-glucose cotransporter 2 inhibitor that improves glycemic control in patients with type II diabetes mellitus (T2DM) by reducing renal glucose reabsorption.

OBJECTIVE

The aim was to evaluate the lipid effects of dapagliflozin 10 mg or placebo in patients with T2DM with/without baseline elevated triglyceride and reduced high-density lipoprotein (HDL) cholesterol levels.

METHODS

This was a post hoc analysis of 10 phase 3, placebo-controlled studies of dapagliflozin 10 mg (N = 2237) or placebo (N = 2164) administered for 24 weeks in patients with T2DM. Patients with elevated triglyceride (≥150 mg/dL [1.69 mmol/L]) and reduced HDL cholesterol levels (<40 mg/dL [1.04 mmol/L] in men; <50 mg/dL [1.29 mmol/L] in women) were included (group A). The reference group (group B) included patients who did not meet the defined lipid criteria.

RESULTS

The effects of dapagliflozin on fasting lipid profiles were generally similar in the 2 lipid groups (ie, groups A and B) and, compared with placebo, were associated with minor increases in non-HDL cholesterol, low-density lipoprotein, and HDL cholesterol levels. The effects on triglyceride levels were inconsistent. The incidence of adverse events (AEs)/serious AEs, and AEs of genital infection, urinary tract infection, volume reduction, renal function, and hypoglycemia were similar in the 2 lipid groups.

CONCLUSION

Patients with T2DM treated with dapagliflozin experienced minor changes in lipid levels; the changes were generally similar in the 2 lipid groups. The clinical significance of these changes in lipids is unclear, especially in view of the positive effects of dapagliflozin on other cardiovascular disease risk factors.

Non-HDL cholesterol vs. apo B for risk of coronary heart disease in healthy individuals: the EPIC-Norfolk prospective population study

BACKGROUND

There is an ongoing debate about the performance of non-high-density lipoprotein cholesterol (non-HDL-C) compared with apolipoprotein B (apo B) in the prediction of coronary heart disease (CHD) risk. Therefore, we compared the associations between non-HDL-C and apo B in regard to CHD among apparently healthy Western European individuals.

DESIGN

In the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk prospective population study, 25,639 men and women aged 45-79 years were followed for 11·4 ± 2·8 years. Those with diabetes or prevalent CHD at baseline were excluded. A total of 2066 (12·1%) participants developed CHD during 195 692 person-years follow-up.

RESULTS

The multivariable-adjusted hazard ratio [HR] of future CHD per one standard deviation increase was 1·22 [95% confidence interval (CI): 1·17-1·27] for LDL-C, 1·26 (95% CI 1·20-1·31) for non-HDL-C and 1·19 (95% CI 1·14-1·24) for apo B, respectively. The multivariable-adjusted HR of future CHD in the highest quartile LDL-C was 1·67 (95% CI: 1·47-1·91). For non-HDL-C and apo B, these respective HRs were 1·87 (95% CI: 1·62-2·15) and 1·56 (95% CI: 1·36-1·78). Kaplan-Meier survival analyses showed that there was incremental and comparable increase in risk of CHD with increasing quartiles of both non-HDL-C and apo B.

CONCLUSIONS

In this prospective study, non-HDL-C and apo B were comparable in their ability to predict risk of future CHD.

The role of non-HDL cholesterol in risk stratification for coronary artery disease

Despite aggressive lipid-lowering therapy, patients continue to be at significant risk of coronary heart disease (CHD). Assessment of non-high-density lipoprotein cholesterol (non-HDL-C) provides a measure of cholesterol contained in all atherogenic particles. In the third Adult Treatment Panel (ATP III) guidelines of the US National Cholesterol Education Program, non-HDL-C was introduced as a secondary target of therapy in persons with triglycerides ≥200 mg/dL. A recent meta-analysis of the relationship between non-HDL-C reduction and CHD risk showed non-HDL-C as an important target of therapy for CHD prevention. Most lipid-modifying drugs used as monotherapy have a 1:1 relationship between percent non-HDL-C lowering and percent CHD reduction. In the EPIC-Norfolk prospective population study, 21,448 participants without diabetes or CHD between 45 and 79 years of age were followed for 11.0 years. Participants with high non-HDL-C levels were at increased CHD risk independently of their LDL-C levels. Also, compared to apolipoprotein B, non-HDL-C appears to be a better choice given the fact that no additional tests or costs are needed and established cut points are already available. Future guidelines should emphasize the importance of non-HDL-C for guiding cardiovascular prevention strategies with an increased need to have non-HDL-C reported on routine lipid panels.

Quantification of concordance and discordance between apolipoprotein-B and the currently recommended non-HDL-cholesterol goals for cardiovascular risk assessment in patients with diabetes and hypertriglyceridemia

AIMS

In patients with diabetes and hypertriglyceridemia, LDL-cholesterol (LDL-C) provides an inaccurate reflection of LDL particle burden. The relative value of non-HDL-cholesterol (non-HDL-C) and apolipoprotein-B (Apo-B) in estimating cardiovascular risk is controversial. We assessed the discordance between non-HDL-C and Apo-B targets in patients with diabetes with TG 200-499 mg/dl.

METHODS

Data from 1430 determinations of LDL-C, non-HDL-C, and Apo-B in ambulatory patients with diabetes were analyzed. Rates of discordance were calculated, based on the currently recommended LDL-C, non-HDL-C, and Apo-B goals.

RESULTS

In patients with non-HDL-C goal of <130 mg/dl, there was a discordance with Apo-B level goal of <90 mg/dl, in 31% of samples. In patients with non-HDL-C goal of <100 mg/dl, 6% of samples had Apo-B ≥80 and 18% had Apo-B <80 mg/dl. Using the Apo-B goal of <70 mg/dl, these numbers were 37% and 3.5% respectively. There was also a significant gender difference, i.e. under-estimation of risk by suggested non-HDL-C cut-offs, in females, compared to males.

CONCLUSIONS

In patients with diabetes and hypertriglyceridemia, a considerable discordance exists between non-HDL-C and Apo-B. Our data suggest a need for prospective studies to compare the relative merits of non-HDL-C and Apo-B targets in the assessment of cardiovascular risk.

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.