Add-on ezetimibe treatment to low-dose statins vs medium-intensity statin monotherapy in coronary artery disease patients with poorly controlled dyslipidemia

Expanding the therapeutic landscape: ezetimibe as non-statin therapy for dyslipidemia

Dyslipidemia is a significant risk factor for atherosclerotic cardiovascular disease (ASCVD), and statins are the primary therapeutic options for reducing low-density lipoprotein cholesterol (LDL-C) levels. However, it can be challenging to achieve optimal LDL-C goals with statin monotherapy. Ezetimibe, a cholesterol absorption inhibitor, offers a potential non-statin therapy to optimize LDL-C management. Key clinical trials, such as IMPROVE-IT and RACING, have demonstrated that the addition of ezetimibe to statin therapy leads to further decreases in LDL-C or significant decreases in major adverse cardiovascular events (MACEs), particularly in patients with high ASCVD risk. Subsequent meta-analyses and clinical trials have further supported the beneficial effect of ezetimibe, suggesting additive decreases in LDL-C and MACEs, as well as pleiotropic effects. This review provides a comprehensive analysis of the clinical implications of ezetimibe for managing dyslipidemia; it also evaluates the available evidence that supports the role of ezetimibe as an adjunct non-statin therapy for long-term use. However, the long-term pleiotropic effects of ezetimibe remain controversial because of limited clinical data. Therefore, additional research is needed to clarify its potential benefits beyond LDL-C reduction. Nonetheless, an understanding of the role of ezetimibe in dyslipidemia management will help clinicians to develop effective treatment strategies.

Disparities in PCSK9 Initiation Among US Veterans with Peripheral Arterial Disease or Cerebrovascular Disease

BACKGROUND

Effective lipid lowering is essential in patients with peripheral arterial disease (PAD) and cerebrovascular disease (CeVD). Proprotein convertase subtilsin/kexin type 9 inhibitors (PCSK9i) efficiently lower low-density lipoprotein (LDL) levels; however, use in PAD and CeVD patients is limited. Therefore, our aim was to evaluate the use of PCSK9i among US Veterans and compare rates between patients with PAD, CeVD, and coronary artery disease (CAD).

METHODS

We evaluated PCSK9i initiation (2016-2019) in US Veterans with CAD, PAD, or CeVD treated at 124 Veterans Affairs (VA) hospitals. We fit a hierarchical logistic regression model to evaluate the association of the patient's primary diagnosis, baseline low-density lipoprotein cholesterol (LDL-C) levels, socioeconomic indicators, and the Department of Veterans Affairs medical center enrollment with PCSK9i initiation.

RESULTS

Of 519,566 patients with atherosclerotic vascular disease, 337,766 (65%), 79,926 (15%) and 101,874 (20%) had CAD, PAD, and CeVD, respectively. Among 2115/519,566 (0.4%) initiated on PCSK9i therapy, 84.3% had CAD, while only 7.2% and 8.5% had PAD and CeVD, respectively. Compared with CAD patients, PAD {odds ratio [OR] 0.50 (0.36-0.70)} and CeVD [OR 0.24 (0.15-0.37)] patients were less likely to receive PCSK9i. Relative to under $40K per year, PCSK9i initiation was higher if earning $40,000-$80,000 [OR 1.13 (1.01-1.27)] or > $80,000 [OR 1.41 (1.14-1.75)]. Even moderate community deprivation [OR 0.87 (0.77-0.97)] was associated with lower PCSK9i therapy.

CONCLUSIONS

Adjusted for LDL-C levels, PAD and CeVD patients are much less likely to receive PCSK9i therapy. Despite low co-pay, PCSK9i initiation rates among US veterans, nationwide, is low, with household income and community deprivation appearing to predict PCSK9i use.

Atherogenic Lipoproteins for the Statin Residual Cardiovascular Disease Risk

Randomized controlled trials (RCTs) show that decreases in low-density lipoprotein cholesterol (LDL-C) by the use of statins cause a significant reduction in the development of cardiovascular disease (CVD). However, one of our previous studies showed that, among eight RCTs that investigated the effect of statins vs. a placebo on CVD development, 56–79% of patients had residual CVD risk after the trials. In three RCTs that investigated the effect of a high dose vs. a usual dose of statins on CVD development, 78–87% of patients in the high-dose statin arms still had residual CVD risk. The risk of CVD development remains even when statins are used to strongly reduce LDL-C, and this type of risk is now regarded as statin residual CVD risk. Our study shows that elevated triglyceride (TG) levels, reduced high-density lipoprotein cholesterol (HDL-C), and the existence of obesity/insulin resistance and diabetes may be important metabolic factors that determine statin residual CVD risk. Here, we discuss atherogenic lipoproteins that were not investigated in such RCTs, such as lipoprotein (a) (Lp(a)), remnant lipoproteins, malondialdehyde-modified LDL (MDA-LDL), and small-dense LDL (Sd-LDL). Lp(a) is under strong genetic control by apolipoprotein (a), which is an LPA gene locus. Variations in the LPA gene account for 91% of the variability in the plasma concentration of Lp(a). A meta-analysis showed that genetic variations at the LPA locus are associated with CVD events during statin therapy, independent of the extent of LDL lowering, providing support for exploring strategies targeting circulating concentrations of Lp(a) to reduce CVD events in patients receiving statins. Remnant lipoproteins and small-dense LDL are highly associated with high TG levels, low HDL-C, and obesity/insulin resistance. MDA-LDL is a representative form of oxidized LDL and plays important roles in the formation and development of the primary lesions of atherosclerosis. MDA-LDL levels were higher in CVD patients and diabetic patients than in the control subjects. Furthermore, we demonstrated the atherogenic properties of such lipoproteins and their association with CVD as well as therapeutic approaches.

The Effects of Statin Dose, Lipophilicity, and Combination of Statins plus Ezetimibe on Circulating Oxidized Low-Density Lipoprotein Levels: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Elevated plasma low-density lipoprotein cholesterol (LDL-C) is the main risk factor for atherosclerotic cardiovascular disease (ASCVD). Statins are the drugs of choice for decreasing LDL-C and are used for the prevention and management of ASCVD. Guidelines recommend that subjects with high and very high ASCVD risk should be treated with high-intensity statins or a combination of high-intensity statins and ezetimibe. The lipophilicity or hydrophilicity (solubility) of statins is considered to be important for at least some of their LDL-C lowering independent pleiotropic effects. Oxidative modification of LDL (ox-LDL) is considered to be the most important atherogenic modification of LDL and is supposed to play a crucial role in atherogenesis and ASCVD outcomes.

Objective

The aim of this systematic review and meta-analysis was to find out what are the effects of statin intensity, lipophilicity, and combination of statins plus ezetimibe on ox-LDL.

Methods

PubMed, Scopus, Embase, and Web of Science were searched from inception to February 5, 2021, for randomized controlled trials (RCTs). Two independent and blinded authors evaluated eligibility by screening the titles and abstracts of the studies. Risk of bias in the studies included in this meta-analysis was evaluated according to the Cochrane instructions. Meta-analysis was performed using Comprehensive Meta-Analysis (CMA) V2 software. Evaluation of funnel plot, Begg's rank correlation, and Egger's weighted regression tests were used to assess the presence of publication bias.

Results

Among the 1427 published studies identified by a systematic databases search, 20 RCTs were finally included in the systematic review and meta-analysis. A total of 1874 patients are included in this meta-analysis. This meta-analysis suggests that high-intensity statin treatment is associated with a significant decrease in circulating concentrations of ox-LDL when compared with low-to-moderate treatment (SMD: -0.675, 95% CI: -0.994, -0.357, p < 0.001; I²: 55.93%). There was no difference concerning ox-LDL concentration between treatments with hydrophilic and lipophilic statins (SMD: -0.129, 95% CI: -0.330, -0.071, p = 0.206; I²: 45.3%), but there was a significant reduction in circulating concentrations of ox-LDL associated with statin plus ezetimibe combination therapy when compared with statin monotherapy (SMD: -0.220, 95% CI: -0.369, -0.071, p = 0.004; I²: 0%).

Conclusion

High-dose statin or combination of statins with ezetmibe reduces plasma ox-LDL in comparison low-to-moderate intensity statin therapy alone. Statin lipophilicity is not associated with reduction in ox-LDL plasma concentrations.

Efficacy of Statin/Ezetimibe for Secondary Prevention of Atherosclerotic Cardiovascular Disease in Asian Populations: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Several clinical trials have investigated the effect of statin/ezetimibe combination therapy on secondary prevention of atherosclerotic cardiovascular disease (ASCVD) in the Asian population.

OBJECTIVE

This study aimed to summarize study results regarding the effect of statin/ezetimibe combination therapy on lipid parameters and highly sensitive C-reactive protein (HsCRP) biomarkers in ASCVD patients from Asian countries.

METHODS

We searched the PubMed/MEDLINE, Web of Science, Scopus, and Google Scholar databases for relevant papers published from 2008 to June 2020. We included randomized controlled trials (RCTs) that (1) were conducted in ASCVD patients in Asian countries; (2) examined the effects of statin/ezetimibe combination therapies compared with a control group; and (3) reported sufficient data on lipid parameters and HsCRP biomarkers. The results were reported as weighted mean differences (WMDs) with 95% confidence intervals (CI) using random-effects models. Funnel plots and Egger's regression test were used to assess publication bias.

RESULTS

Twenty-four RCTs were reviewed and 20 were included in the meta-analysis. A total of 4344 participants were included (n = 2197 in the intervention group and n = 2147 in the control group), and the intervention durations ranged from 6 weeks to 3.6 years. Ezetimibe coadministered with statin therapy, compared with control treatment, significantly reduced low-density lipoprotein cholesterol (LDL-C; n = 20 studies) [WMD  - 0.39 mmol/L, 95% CI - 0.73 to - 0.05; p < 0.001], triglycerides (TG; n = 18 studies) [WMD - 0.23 mmol/L, 95% CI - 0.33 to - 0.13; p < 0.001], and total cholesterol (TC; n = 17 studies) [WMD - 0.31 mmol/L, 95% CI - 0.45 to - 0.17; p < 0.001). Although the effect of statin/ezetimibe combinations on high-density lipoprotein cholesterol (HDL-C; n = 17 studies) [WMD 0.02 mmol/L, 95% CI - 0.05 to 0.09; p < 0.001) was very minimal and no effect was observed on HsCRP levels (n = 11 studies).

CONCLUSIONS

Our study found that statin/ezetimibe combinations reduced LDL-C, TC, and TG levels but had minimal effects on HDL-C and no effect HsCRP biomarkers in ASCVD patients. The statin/ezetimibe therapy enabled a more effective reduction in LDL-C levels; however, the duration of the treatment was suboptimal.