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

Association of baseline serum cholesterol with benefits of intensive blood pressure control

BACKGROUND

Intensive systolic blood pressure (SBP) control improved outcomes in the Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients (STEP) trial. Whether baseline serum lipid parameters influence the benefits of intensive SBP control is unclear.

METHODS

The STEP trial was a randomized controlled trial that compared the effects of intensive (SBP target of 110 to <130 mmHg) and standard (SBP target of 130 to <150 mmHg) SBP control in Chinese patients aged 60 to 80 years with hypertension. The primary outcome was a composite of cardiovascular disease events. A total of 8283 participants from the STEP study were included in this post hoc analysis to examine whether the effects of the SBP intervention differed by baseline low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) concentrations.

RESULTS

Regardless of the randomized SBP intervention, baseline LDL-C and non-HDL-C concentrations had a J-shaped association with the hazard of the primary outcome. However, the effects of the intensive SBP intervention on the primary outcome were not influenced by baseline LDL-C level ( P for interaction = 0.80) and non-HDL-C level ( P for interaction = 0.95). Adjusted subgroup analysis using tertiles in LDL-C1 (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.52-1.13; P = 0.18), LDL-C2 (HR, 0.81; 95% CI, 0.55-1.20; P = 0.29), and LDL-C3 (HR, 0.68; 95% CI, 0.47-0.98; P = 0.04) was provided, with an interaction P value of 0.49. Similar results were showed in non-HDL-C1 (HR, 0.87; 95% CI, 0.59-1.29; P = 0.49), non-HDL-C2 (HR, 0.70; 95% CI, 0.48-1.04; P = 0.08), and non-HDL-C3 (HR, 0.67; 95% CI, 0.47-0.95; P = 0.03), with an interaction P -value of 0.47.

CONCLUSION

High baseline serum LDL-C and non-HDL-C concentrations were associated with increased risk of primary cardiovascular disease outcome, but there was no evidence that the benefit of the intensive SBP control differed by baseline LDL-C and non-HDL-C concentrations.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT03015311.

Lipoprotein(a): Its Association with Calcific Aortic Valve Stenosis, the Emerging RNA-Related Treatments and the Hope for a New Era in “Treating” Aortic Valve Calcification

The treatment of patients with aortic valve calcification (AVC) and calcific aortic valve stenosis (CAVS) remains challenging as, until today, all non-invasive interventions have proven fruitless in preventing the disease’s onset and progression. Despite the similarities in the pathogenesis of AVC and atherosclerosis, statins failed to show a favorable effect in preventing AVC progression. The recognition of lipoprotein(a) [Lp(a)] as a strong and potentially modifiable risk factor for the development and, perhaps, the progression of AVC and CAVS and the evolution of novel agents leading in a robust Lp(a) reduction, have rekindled hope for a promising future in the treatment of those patients. Lp(a) seems to promote AVC via a ‘three hit’ mechanism including lipid deposition, inflammation and autotaxin transportation. All of these lead to valve interstitial cells transition into osteoblast-like cells and, thus, to parenchymal calcification. Currently available lipid-lowering therapies have shown a neutral or mild effect on Lp(a), which was proven insufficient to contribute to clinical benefits. The short-term safety and the efficacy of the emerging agents in reducing Lp(a) have been proven; nevertheless, their effect on cardiovascular risk is currently under investigation in phase 3 clinical trials. A positive result of these trials will probably be the spark to test the hypothesis of the modification of AVC’s natural history with the novel Lp(a)-lowering agents.

What should be the goal of cholesterol-lowering treatment? A quantitative evaluation dispelling guideline myths

PURPOSE OF REVIEW

Guidelines for cholesterol-lowering treatment generally include extensive review of epidemiological and clinical trial evidence. However, the next logical step, the translation of evidence into clinical advice, occurs not entirely by reasoning, but by a form of consensus in which the prejudices and established beliefs of the societies with interests in cardiovascular disease convened to interpret the evidence are prominent. Methods, which are the subject of this review, have, however, been developed by which clinical trial evidence can be translated objectively into best practice.

RECENT FINDINGS

Guidelines differ in their recommended goals for cholesterol-lowering treatment in the prevention of atherosclerotic cardiovascular disease (ASCVD). Proposed goals are LDL-cholesterol 2.6 mmol/l (100 mg/dl) or less in lower risk, LDL-cholesterol 1.8 mmol/l (70 mg/dl) or less in higher risk, non-HDL-cholesterol decrease of at least 40% or LDL-cholesterol 1.8 mmol/l (70 mg/dl) or less or decreased by at least 50% whichever is lower. Evidence from clinical trials of statins, ezetimibe and proprotein convertase subtilisin/kexin type 9-inhibitors can be expressed in simple mathematical terms to compare the efficacy on ASCVD incidence of clinical guidance for the use of cholesterol-lowering medication. The target LDL-cholesterol of 2.6 mmol/l (100 mg/dl) is ineffective and lacks credibility. Cholesterol-lowering medication is most effective in high-risk people with raised LDL-cholesterol. The best overall therapeutic target is LDL-cholesterol 1.8 mmol/l (70 mg/dl) or less or decreased by at least 50% whichever is lower. The use of non-HDL-cholesterol as a therapeutic goal is less efficacious. Aiming for LDL-cholesterol 1.4 mmol/l (55 mg/dl) or less as opposed to 1.8 mmol/l produces only a small additional benefit. Evidence for apolipoprotein B targets in hypertriglyceridaemia and in very high ASCVD risk should be more prominent in future guidelines.

SUMMARY

The LDL-cholesterol goal of 2.6 mmol/l or less should be abandoned. Percentage decreases in LDL-cholesterol or non-HDL-cholesterol concentration are better in people with initial concentrations of less than 3.6 mmol/l. The LDL-cholesterol target of 1.8 mmol/l is most effective when initial LDL-cholesterol is more than 3.6 mmol/l in both primary and secondary prevention.

A Modern Approach to Dyslipidemia

Lipid disorders involving derangements in serum cholesterol, triglycerides, or both are commonly encountered in clinical practice and often have implications for cardiovascular risk and overall health. Recent advances in knowledge, recommendations, and treatment options have necessitated an updated approach to these disorders. Older classification schemes have outlived their usefulness, yielding to an approach based on the primary lipid disturbance identified on a routine lipid panel as a practical starting point. Although monogenic dyslipidemias exist and are important to identify, most individuals with lipid disorders have polygenic predisposition, often in the context of secondary factors such as obesity and type 2 diabetes. With regard to cardiovascular disease, elevated low-density lipoprotein cholesterol is essentially causal, and clinical practice guidelines worldwide have recommended treatment thresholds and targets for this variable. Furthermore, recent studies have established elevated triglycerides as a cardiovascular risk factor, whereas depressed high-density lipoprotein cholesterol now appears less contributory than was previously believed. An updated approach to diagnosis and risk assessment may include measurement of secondary lipid variables such as apolipoprotein B and lipoprotein(a), together with selective use of genetic testing to diagnose rare monogenic dyslipidemias such as familial hypercholesterolemia or familial chylomicronemia syndrome. The ongoing development of new agents-especially antisense RNA and monoclonal antibodies-targeting dyslipidemias will provide additional management options, which in turn motivates discussion on how best to incorporate them into current treatment algorithms.

Mathematical modelling of the most effective goal of cholesterol-lowering treatment in primary prevention

OBJECTIVE

To compare quantitatively different recommended goals for cholesterol-lowering treatment in the primary prevention of atherosclerotic cardiovascular disease (ASCVD).

DESIGN

Outcomes at pretreatment low-density lipoprotein (LDL) cholesterol concentrations from 2 to 5 mmol/L and 10-year ASCVD risk from 5% to 30% were modelled, using the decrease in risk ratio per mmol/L reduction in LDL cholesterol derived from randomised controlled trials (RCTs) of cholesterol-lowering medication.

DATA SOURCE

Summary statistics from 26 RCTs comparing treatment versus placebo or less versus more effective treatment and 12 RCTs in which statin was compared with a higher dose of the same statin or with a similar statin dose to which an adjunctive cholesterol-lowering drug was added.

SETTING

The different recommended goals are: (1) LDL cholesterol≤2.6 mmol/L (100 mg/dL); (2) LDL cholesterol≤1.8 mmol/L (70 mg/dL); (3) non-high density lipoprotein (HDL) cholesterol decrease of ≥40%; or (4) LDL cholesterol≤1.8 mmol/L (70 mg/dL) or decreased by ≥50% whichever is lower.

PARTICIPANTS

RCT participants.

INTERVENTIONS

Statins alone or in combination with ezetimibe or proprotein convertase subtilisin/kexin type 9 inhibitors.

MAIN OUTCOME MEASURES

For each of the recommended therapeutic goals, our primary outcome was the number of events prevented per 100 people treated for 10 years (N₁₀₀) and the number of needed to treat (NNT) to prevent one event over 10 years.

RESULTS

At pretreatment LDL cholesterol 4-5 mmol/L, all four goals provided similar benefit with N₁₀₀ 1.47-16.45 (NNT 6-68), depending on ASCVD risk and pretreatment LDL cholesterol. With initial LDL cholesterol in the range 2-3 mmol/L, the target of 2.6 mmol/L was the least effective with N₁₀₀ between 0 and 2.84 (NNT 35-infinity). The goal of 1.8 mmol/L was little better. However, reductions in non-HDL cholesterol by ≥40% or of LDL cholesterol to 1.8 mmol/L and/or by 50%, whichever is lower, were more effective, delivering N₁₀₀ of between 0.9 and 9.33 (NNT 11-111). Percentage decreases in LDL cholesterol or non-HDL cholesterol concentration are more effective targets than absolute change in concentration in people with initial values of <4 mmol/L.

CONCLUSIONS

The LDL cholesterol target of 1.8 mmol/L is most effective when initial LDL cholesterol is >4 mmol/L. The time has probably come for the LDL cholesterol goal of <2.6 mmol/L to be abandoned.

Apolipoprotein B and Cardiovascular Disease: Biomarker and Potential Therapeutic Target

Apolipoprotein (apo) B, the critical structural protein of the atherogenic lipoproteins, has two major isoforms: apoB48 and apoB100. ApoB48 is found in chylomicrons and chylomicron remnants with one apoB48 molecule per chylomicron particle. Similarly, a single apoB100 molecule is contained per particle of very-low-density lipoprotein (VLDL), intermediate density lipoprotein, LDL and lipoprotein(a). This unique one apoB per particle ratio makes plasma apoB concentration a direct measure of the number of circulating atherogenic lipoproteins. ApoB levels indicate the atherogenic particle concentration independent of the particle cholesterol content, which is variable. While LDL, the major cholesterol-carrying serum lipoprotein, is the primary therapeutic target for management and prevention of atherosclerotic cardiovascular disease, there is strong evidence that apoB is a more accurate indicator of cardiovascular risk than either total cholesterol or LDL cholesterol. This review examines multiple aspects of apoB structure and function, with a focus on the controversy over use of apoB as a therapeutic target in clinical practice. Ongoing coronary artery disease residual risk, despite lipid-lowering treatment, has left patients and clinicians with unsatisfactory options for monitoring cardiovascular health. At the present time, the substitution of apoB for LDL-C in cardiovascular disease prevention guidelines has been deemed unjustified, but discussions continue.

Non-HDL or LDL cholesterol in heterozygous familial hypercholesterolaemia: findings of the Simon Broome Register

PURPOSE OF REVIEW

The role of non-HDL-C in the identification and management of lipid disorders is not clearly defined, although UK guidelines recommend its wider use in assessing the need for lipid-lowering therapy and as a treatment target.

RECENT FINDINGS

We examined the implications of the use of non-HDL-C as opposed to LDL-C in 253 people with hypercholesterolaemia before treatment and 573 after treatment in whom fasting total serum cholesterol, HDL-C and LDL-C had been recorded and the diagnosis of heterozygous familial hypercholesterolemia (heFH) was investigated by genetic testing. The difference and the limits of agreement between non-HDL-C and LDL-C calculated using the Friedewald formula were assessed in those with and without heFH-causing mutations.

SUMMARY

There were 147 mutation-positive and 106 mutation-negative pretreatment participants and 395 mutation-positive and 178 mutation-negative patients receiving treatment. The difference between non-HDL-C and LDL-C pretreatment in mutation-positive people (mean LDL-C 7.73 mmol/l) was 0.67 mmol/l (95% CI 0.62-0.73) and posttreatment (mean LDL-C 4.71 mmol/l) was 0.62 mmol/l (95% CI 0.59-0.65) with wide limits of agreement of -0.02 to 1.37 and 0.07-1.18 mmol/l, respectively. Among patients with heterozygous familial hypercholesterolaemia, use of estimated LDL-C derived from non-HDL-C in place of calculated LDL-C may result in diagnostic misclassification and difficulty in assessing the true reduction in LDL-C with treatment, because of the wide inter-individual limits of agreement around the mean difference between non-HDL-C and LDL-C.

Pediatric Dyslipidemia-Beyond Familial Hypercholesterolemia

Dyslipidemia is seen with increasing prevalence in young Canadians, mainly mild to moderate hypertriglyceridemia secondary to obesity. This review focuses on pediatric dyslipidemias excluding familial hypercholesterolemia (FH), but including both severe and mild to moderate hypertriglyceridemia, combined hyperlipidemia, and elevated lipoprotein(a) [Lp(a)]. We suggest that for Canadian children and adolescents with dyslipidemia, atherosclerotic cardiovascular disease (ASCVD) risk assessment should include both low-density lipoprotein cholesterol and triglyceride measurement. To further stratify risk, determination of non-high-density lipoprotein cholesterol is recommended, for both its ability to predict ASCVD and convenience for the patient because fasting is not required. Similarly, apolipoprotein B measurement (fasting or nonfasting), where available, can be helpful. Lp(a) measurement should not be routine in childhood, but it can be considered in special circumstances. After ruling out secondary causes, the foundation for management of pediatric dyslipidemia includes weight regulation, optimizing diet, and increasing activity level. At present, randomized clinical trial data to guide pharmaceutical management of pediatric hypertriglyceridemia or other non-FH pediatric dyslipidemias are scarce. Pharmaceutical management should be reserved for special situations in which risk of complications such as acute pancreatitis or ASCVD over the intermediate term is high and conservative lifestyle-based interventions have been ineffective.