Baseline serum sitosterol level as predictor of adverse clinical events in acute coronary syndrome patients with dyslipidaemia: A sub-analysis of HIJ-PROPER

The profile of cholesterol metabolism does not interfere with the cholesterol-lowering efficacy of phytostanol esters

BACKGROUND & AIMS

Increasing evidence suggests that high cholesterol absorption efficiency enhances the risk of atherosclerotic cardiovascular diseases. It is not known whether inhibiting cholesterol absorption has different metabolic effects in high- vs. low cholesterol absorbers. We evaluated the effects of phytostanol esters on serum lipids and cholesterol metabolism in a post hoc study of three randomized, double-blind, controlled trials. The participants were classified into low (n = 20) and high (n = 21) cholesterol absorbers by median cholesterol absorption efficiency based on the plasma cholesterol absorption marker cholestanol at baseline.

METHODS

The participants consumed mayonnaise or margarine without or with phytostanol esters for six to nine weeks without other changes in the diet or lifestyle. Serum cholesterol, cholestanol, lathosterol, and faecal neutral sterols and bile acids were analysed by gas-liquid chromatography. According to power calculations, the size of the study population (n = 41) was appropriate.

RESULTS

During the control period, cholesterol synthesis, and faecal neutral sterols and bile acids were lower in high- vs. low absorbers (p < 0.05 for all). Phytostanol esters reduced low-density lipoprotein cholesterol by 10-13% in both groups, and directly measured cholesterol absorption efficiency by 41 ± 7% in low- and 47 ± 5% in high absorbers (p < 0.001 for all) without side effects. Cholesterol synthesis and faecal neutral sterols (p < 0.01) increased in both groups, more markedly in the high vs. low absorbers (p < 0.01).

CONCLUSIONS

Low cholesterol absorption combined with high faecal neutral sterol excretion are components of reverse cholesterol transport. Thus, high- vs. low absorbers had a more disadvantageous metabolic profile at baseline. In both groups, phytostanol esters induced favourable changes in serum, lipoprotein, and metabolic variables known to help in prevention of the development of atherosclerotic cardiovascular diseases.

Higher Cholesterol Absorption Marker at Baseline Predicts Fewer Cardiovascular Events in Elderly Patients Receiving Hypercholesterolemia Treatment: The KEEP Study

BACKGROUND

Higher cholesterol absorption has been reported to be related to a higher incidence of cardiovascular events (CVEs). The KEEP (Kyushu Elderly Ezetimibe Phytosterol) study, a substudy of the EWTOPIA 75 (Ezetimibe Lipid-Lowering Trial on Prevention of Atherosclerotic Cardiovascular Disease in 75 or Older) study, investigated the relationships of cholesterol absorption and synthesis markers with CVEs in older old individuals with hypercholesterolemia, particularly in relation to ezetimibe treatment.

METHODS AND RESULTS

Eligible patients were those aged ≥75 years who had low-density lipoprotein cholesterol ≥140 mg/dL, no history of coronary artery disease, and no recent use of lipid-lowering drugs. Participants were randomly assigned into a diet-only or diet-plus-ezetimibe group. Baseline and 24-week follow-up blood samples were analyzed for cholesterol absorption (eg, campesterol) and synthesis markers (eg, lathosterol). Of 1287 patients, 1061 patients with baseline measurement were analyzed. Over a median follow-up of 4.0 years, 64 CVEs occurred. Higher campesterol levels at baseline were significantly associated with a lower risk of CVEs. After adjustment for sex, age, and treatment, the hazard ratios for the lowest to highest quartile categories of baseline campesterol were 1.00 (reference), 0.59 (95% CI, 0.30-1.17), 0.44 (95% CI, 0.21-0.94), and 0.44 (95% CI, 0.21-0.93), respectively (trend P=0.01). This association persisted after further adjustment for hypertension, diabetes, and other cardiovascular risk factors. Neither interactions with ezetimibe treatment nor mediating effects of the changes in cholesterol absorption markers were observed.

CONCLUSIONS

The KEEP study indicated that higher campesterol levels without lipid-lowering drugs were associated with a lower incidence of CVEs in older old individuals with hypercholesterolemia who were subsequently treated with diet or ezetimibe.

REGISTRATION

URL: https://www.umin.ac.jp; unique identifier: UMIN000017769.

Oxy- and Phytosterols as Biomarkers: Current Status and Future Perspectives

Oxysterols and phytosterols are sterol compounds present at markedly low levels in tissues and serum of healthy individuals. A wealth of evidence suggests that they could be employed as biomarkers for human diseases or for cholesterol absorption.An increasing number of reports suggest circulating or tissue oxysterols as putative biomarkers for cardiovascular and neurodegenerative diseases or cancers. Thus far most of the studies have been carried out on small study populations. To achieve routine biomarker use, large prospective cohort studies are absolutely required. This, again, would necessitate thorough standardization of the oxysterol analytical methodology across the different laboratories, which now employ different technologies resulting in inconsistencies in the measured oxysterol levels. Routine use of oxysterol biomarkers would also necessitate the development of a new targeted analytical methodology suitable for high-throughput platforms.The most important use of phytosterols as biomarkers involves their use as markers for cholesterol absorption. For this to be achieved, (1) their quantitative analyses should be available in routine lipid laboratories, (2) it should be generally acknowledgment that the profile of cholesterol metabolism can reveal the risk of the development of atherosclerotic cardiovascular diseases (ASCVD), and (3) screening of the profile of cholesterol metabolism should be included in the ASCVD risk surveys. This should be done e.g. in families with a history of early onset or frequent ASCVD and in young adults aged 18-20 years, to exclude the presence of high cholesterol absorption. Individuals in high cholesterol absorption families need preventive measures from young adulthood to inhibit the possible development and progression of atherosclerosis.

Efficacy and Safety of Pitavastatin/Ezetimibe Fixed-Dose Combination vs. Pitavastatin: Phase III, Double-Blind, Randomized Controlled Trial

AIM

We compared the efficacy and safety of pitavastatin/ezetimibe fixed-dose combination with those of pitavastatin monotherapy in patients with hypercholesterolemia.

METHODS

This trial was a multicenter, randomized, double-blind, active-controlled, parallel-group trial. A total of 293 patients were randomly assigned into four groups receiving 2 mg pitavastatin, 4 mg pitavastatin, 2 mg pitavastatin/10 mg ezetimibe (K-924 LD), and 4 mg pitavastatin/10 mg ezetimibe (K-924 HD) once daily for 12 weeks.

RESULTS

The percentage changes in low-density lipoprotein cholesterol (LDL-C), the primary endpoint, were -39.5% for 2 mg pitavastatin, -45.2% for 4 mg pitavastatin, -51.4% for K-924 LD, and -57.8% for K-924 HD. Compared with pitavastatin monotherapy, the pitavastatin/ezetimibe fixed-dose combination significantly reduced LDL-C, total cholesterol, and non-high-density lipoprotein cholesterol. Meanwhile, the cholesterol synthesis marker, lathosterol, was significantly decreased with pitavastatin monotherapy and the pitavastatin/ezetimibe fixed-dose combination, although the decrease was attenuated in the latter. On the other hand, the cholesterol absorption markers, beta-sitosterol and campesterol, were reduced with the fixed-dose combination but not with pitavastatin monotherapy. The incidence of adverse events and adverse drug reactions was not significantly different between the two groups receiving the fixed-dose combination and monotherapy. The mean values of laboratory tests that are related to liver function and myopathy increased but remained within the reference range in all groups.

CONCLUSIONS

The pitavastatin/ezetimibe fixed-dose combination showed an excellent LDL-C-reducing effect by the complementary pharmacological action of each component, and its safety profile was similar to that of pitavastatin monotherapy (ClinicalTrials.gov Identifier: NCT04289649).

High cholesterol absorption: A risk factor of atherosclerotic cardiovascular diseases?

Lowering elevated low-density lipoprotein cholesterol (LDL-C) concentrations reduces the risk of atherosclerotic cardiovascular diseases (ASCVDs). However, increasing evidence suggests that cholesterol metabolism may also be involved in the risk reduction of ASCVD events. In this review, we discuss if the different profiles of cholesterol metabolism, with a focus on high cholesterol absorption, are atherogenic, and what could be the possible mechanisms. The potential associations of cholesterol metabolism and the risk of ASCVDs are evaluated from genetic, metabolic, and population-based studies and lipid-lowering interventions. According to these studies, loss-of-function genetic variations in the small intestinal sterol transporters ABCG5 and ABCG8 result in high cholesterol absorption associated with low cholesterol synthesis, low cholesterol elimination from the body, and a high risk of ASCVDs. In contrast, loss-of-function genetic variations in another intestinal sterol transporter, NPC1L1 result in low cholesterol absorption associated with high cholesterol synthesis, elevated cholesterol elimination from the body, and low risk of ASCVDs. Statin monotherapy is not sufficient to reduce the ASCVD risk in cases of high cholesterol absorption, and these individuals need combination therapy of statin with cholesterol absorption inhibition. High cholesterol absorption, i.e., >60%, is estimated to occur in approximately one third of a population, so taking it into consideration is important to optimise lipid-lowering therapy to prevent atherosclerosis and reduce the risk of ASCVD events.

Xenosterolemia in clinical practice: what is in a name?

PURPOSE OF REVIEW

The aim of this study was to assess the potential value of the measurement of plasma xenosterols (or phytosterols) concentrations in clinical practice.

RECENT FINDINGS

Recent genetic studies suggest that individuals with elevated plasma phytosterol concentrations due to monogenic and polygenic variants are at an increased risk of coronary artery disease. This supports early observations that elevated plasma phytosterol concentrations are per se atherogenic.

SUMMARY

Measurement of plasma phytosterols can identify individuals with xenosterolemia (or phytosterolemia). This may be clinically useful in four ways: Establishing a diagnosis and informing management of patients with homozygous phytosterolemia; Providing a comprehensive differential diagnosis for familial hypercholesterolemia; Providing an index of cholesterol absorption that may inform personalized pharmacotherapy; and Informing more precise assessment of risk of cardiovascular disease.

Could Lowering Phytosterol Absorption as Part of Lipid-Lowering Therapy Have a Beneficial Effect on Residual Risk?

Plant sterols are molecules that are structurally similar to cholesterol and provided only as dietary sources (e.g., vegetables, fruits, nuts, cereals) since they cannot be synthesized by humans. Sterol-enriched diets (≥2 g/day) may decrease total and low-density lipoprotein cholesterol concentrations by 5-10%, either alone or when added to statins, since they antagonize dietary cholesterol absorption in the intestine. On the other hand, increased serum phytosterol concentrations, (including when associated with sitosterolemia, a rare genetic defect) may contribute to atherosclerotic risk, although a threshold for such a role has not been established. Medications such as ezetimibe may effectively reduce cholesterol and phytosterol absorption. Whether the therapeutic approach associated with the reduction of phytosterol absorption is also translated into a reduction in a patient's residual cardiovascular risk needs to be established.

Increased cholesterol absorption is associated with In-stent-restenosis after stent implantation for stable coronary artery disease

BACKGROUND AND AIMS

Blood cholesterol levels are regulated by competing mechanisms of cholesterol synthesis, absorption and excretion. Plant sterols are natural constituents of plants, are not synthesized in humans, and serve as markers for cholesterol absorption. Ezetimibe lowers the intestinal absorption of cholesterol and plant sterols. We analyzed the associations of differences in cholesterol metabolism, in particular increased cholesterol absorption, and the occurrence of in-stent restenosis (ISR) in patients with stable coronary artery disease.

METHODS

Elective stent implantation of de novo stenosis was conducted in 59 patients (74.6 % males, 67.2 ± 9.6 years). Cholesterol and non-cholesterol sterols were quantified in serum samples by gas chromatography or mass spectrometry. ISR was assessed by optical coherence tomography (OCT) and quantitative angiography (QCA) after six months.

RESULTS

Markers for cholesterol absorption (e.g. campesterol-to-cholesterol) were positively associated with ISR measured by QCA (%diameter stenosis, late lumen loss) and OCT (proliferation volume, %area stenosis), whereas markers for cholesterol synthesis (e.g. lathosterol-to-cholesterol) were negatively associated with ISR (%area stenosis: r = -0.271, p = 0.043). There was no association between ISR and total cholesterol, LDL, HDL, triglycerides. Markers for cholesterol absorption (e.g. campesterol-to-cholesterol) were significantly lower in ezetimibe-treated patients compared to patients on a statin only (1.29 ± 0.69 vs. 2.22 ± 1.23; p = 0.007). Combined lipid-lowering with ezetimibe plus statin reduced ISR compared to statin only (13.7 ± 10.4 vs. 22.5 ± 12.1 %diameter stenosis, p = 0.015).

CONCLUSIONS

Differences in cholesterol metabolism, more specifically increased cholesterol absorption, are associated with ISR.

Markers of cholesterol synthesis to cholesterol absorption across the spectrum of non-dialysis CKD: An observational study

In dialysis patients, cholesterol-lowering therapy with statins is less effective than in other high-risk patients. This may be explained by a shift from cholesterol synthesis toward cholesterol absorption. In line, markers of cholesterol absorption-such as campesterol-better predict atherosclerotic cardiovascular events than markers of cholesterol synthesis-such as lathosterol-in dialysis patients. To test the association between markers of cholesterol absorption such as campesterol-and markers of cholesterol synthesis-such as lathosterol-against cardiovascular events in non-dialysis CKD patients. Altogether 251 patients those not on lipid-lowering agents were followed annually for the composite endpoint atherosclerotic cardiovascular disease (ASCVD) and all-cause death. During follow-up of 5.2 ± 2.1 years, 61 participants reached the primary endpoint atherosclerotic cardiovascular disease/all-cause death [ASCVD/D], 47 participants suffered from ASCVD, and 46 participants died. In univariate Cox regression analysis, campesterol/lathosterol ratio did not significantly predict ASCVD/D (HR 0.643; 0.358-1.155; 3rd vs. 1st tertile), all-cause death (HR 1.309; 0.604-2.838; 3rd vs. 1st tertile) nor ASCVD (HR 0.589; 0.311-1.118; 3rd vs. 1st tertile). We did not observe a shift from cholesterol synthesis to cholesterol absorption across the spectrum of non-dialysis CKD. Campesterol/lathosterol ratio did not predict future ASCVD or all-cause death in non-dialysis CKD.

Baseline low-density lipoprotein cholesterol predicts the benefit of adding ezetimibe on statin in statin-naïve acute coronary syndrome

We aimed to evaluate the effect of baseline low-density lipoprotein cholesterol (LDL-C) on the outcomes of patients with the acute coronary syndrome (ACS) receiving pitavastatin monotherapy or the combination of pitavastatin + ezetimibe. In the HIJ-PROPER study, 1734 ACS patients with dyslipidemia were randomly assigned to receive pitavastatin or pitavastatin + ezetimibe therapy. Statin-naïve participants (n = 1429) were divided into two groups based on the median LDL-C level (131 mg/dL) at enrollment. The primary endpoint was a composite of all-cause death, non-fatal myocardial infarction, non-fatal stroke, unstable angina, and ischemia-driven coronary revascularization. The median follow-up was 3.2 years. In the < 131 mg/dL group (n = 686), LDL-C changes were − 34.0% and − 49.8% in the pitavastatin monotherapy and pitavastatin + ezetimibe-treated groups (P < 0.0001), respectively; in the ≥ 131 mg/dL group (n = 743), LDL-C changes were − 42.9% and − 56.4% (P < 0.0001, respectively. Kaplan–Meier analyses revealed that the primary endpoint was not significantly different between the treatment groups for the < 131 mg/dL group, however, it was significantly lower in patients treated with pitavastatin + ezetimibe in the ≥ 131 mg/dL group (Hazard ratio = 0.72, 95% confidence interval = 0.56–0.91, P = 0.007, P value for interaction = 0.012). Statin-naïve ACS patients with baseline LDL-C < 131 mg/dL did not clinically benefit from pitavastatin + ezetimibe, while patients with baseline LDL-C ≥ 131 mg/dL treated with pitavastatin + ezetimibe showed better clinical results than those treated with pitavastatin monotherapy.

Clinical Trial Registration: Original HIJ PROPER study; URL: http://www.umin.ac.jp/ctr. Unique Identifier; UMIN000002742, registered as an International Standard Randomized Controlled Trial.

Recent advances in ABCG5 and ABCG8 variants

PURPOSE OF REVIEW

In this review, we summarize the genetics and mechanisms of sitosterolemia and sterol trafficking, and provide an update on the understanding of the prevalence of ABCG5 and ABCG8 variants and their role in human disease.

RECENT FINDINGS

Defects in ABCG5/G8 result in the accumulation of xenosterols. It had been previously thought that near total LoF of one of the proteins was required to cause pathology. However, recently there was the first report of a patient with Sitosterolemia who was heterozygous for mutations in both genes. Moreover, large population studies have demonstrated the even simple heterozygous carriers are associated with altered lipid profiles and cardiovascular risk. Broader screening has added to the rapidly growing list of gene variants indicating that the prevalence of ABCG5/G8 variants is higher than previous thought, especially in patients with hypercholesterolemia.

SUMMARY

These findings support a strategy of measuring xenosterol levels in patients with hypercholesterolemia to screen for ABCG5/G8 variants, and then tailoring treatment with a sterol absorption inhibitor, like ezetimibe, where indicated. Xenosterol trafficking affects remnant clearance and maybe pathogenically linked to the increased risk of atherosclerosis.

It’s time to personalize and optimize lipid-lowering therapy

Collapse

Low-Density Lipoprotein Cholesterol Level cannot be too Low: Considerations from Clinical Trials, Human Genetics, and Biology

LDL cholesterol is by far the best established "causal" cardiovascular risk. It is distributed normally, and the mean value ranges around 100~120 mg/dl. In terms of preventive cardiology, we now know very well that the lower the LDL cholesterol, the better. Clinical usefulness of aggressive LDL-lowering therapies using statin, ezetimibe, and proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors have been shown in primary and in secondary prevention settings. Additionally, the idea, based on recent randomized controlled trials (RCT), that the lower LDL cholesterol the better appears to be true for LDL as low as ~ 30 mg/dl. According to those data, recent guidelines in Europe and in Japan suggest the lowering of LDL cholesterol level ＜70 mg/dl for high-risk patients. However, the attainment rates of such "strict" goals seem to be quite low, probably because most cardiologists still have a sense of anxiety of "low" LDL cholesterol level. But "low" indicates no more than "lower" than the "average" range, which is not always implying the optimal range. Additionally, Mendelian randomization studies focusing on individuals exhibiting "low" LDL cholesterol suggest that "normal" LDL cholesterol levels might be too much for us. Moreover, LDL cholesterol levels of other primates are substantially lower than those in humans. In this review article, based on a series of evidence from clinical trials, human genetics, and biology, we provide the idea that we need to rethink what is the optimal range of LDL cholesterol level, instead of "normal" or "average" range.

Lower levels of high-density lipoprotein cholesterol are associated with increased cardiovascular events in patients with acute coronary syndrome

BACKGROUND AND AIMS

This study aimed to elucidate whether high-density lipoprotein cholesterol (HDL-C) at 3-month follow-up for patients receiving contemporary lipid-lowering therapy after acute coronary syndrome (ACS) could predict cardiac events.

METHODS

The HIJ-PROPER study was a multicenter, prospective, randomized trial comparing intensive lipid-lowering therapy (pitavastatin + ezetimibe) and conventional lipid-lowering therapy (pitavastatin monotherapy) after ACS. The entire cohort was divided into three groups according to tertiles of HDL-C levels at 3-month follow-up (Group 1, HDL-C ≤43 mg/dL; Group 2, HDL-C >43, <53.6 mg/dL; Group 3; HDL-C ≥53.6 mg/dL). Baseline characteristics and incidence of the primary endpoint (a composite of all-cause death, non-fatal myocardial infarction, non-fatal stroke, unstable angina pectoris, or ischemia-driven revascularization) were compared among the three groups.

RESULTS

The primary endpoint event occurred in 34.8%, 30.1%, and 24.6% of patients in Groups 1, 2, and 3, respectively, and its incidence was significantly higher in Group 1 than in Group 3 (hazard ratio [HR], 1.5; 95% confidence interval [CI], 1.19-1.9; p = 0.001). Irrespective of the treatment regimen, Group 1 had significantly higher rates of the primary endpoint than Group 3 (pitavastatin + ezetimibe therapy: HR, 1.6; 95% CI, 1.12-2.22; p = 0.01 and pitavastatin monotherapy: HR, 1.4; 95% CI, 1.05-1.98; p = 0.02). These trends remained even after adjustment for baseline characteristics and lipid profiles. Multivariate analysis revealed that lower body mass index, prevalence of diabetes mellitus, higher levels of high-sensitivity C reactive protein at baseline, and lower levels of HDL-C at 3-month follow-up were independent predictors of the incidence of primary endpoint.

CONCLUSIONS

Lower levels of HDL-C at 3-month follow-up are independently associated with higher incidence of cardiovascular events in ACS patients receiving contemporary lipid-lowering therapy.

Beneficial effect of ezetimibe-atorvastatin combination therapy in patients with a mutation in ABCG5 or ABCG8 gene

Background

Use of ezetimibe on top of statin therapy has been shown to be effective to reduce LDL cholesterol level in hypercholesterolemic patients. However, little is known regarding the individual variety of the effectiveness of ezetimibe. We hypothesized that hypercholesterolemic patients with a mutation in ABCG5 or ABCG8 gene exhibit better response to ezetimibe than those without, based on the fact that ezetimibe is hyper-effective for in patients with sitosterolemia caused by ABCG5 or ABCG8 genetic mutations.

Methods

Electronical medical record were reviewed in a total of 321 hypercholesterolemic patients (baseline LDL cholesterol = 192 ± 46 mg/dl) prescribed ezetimibe 10 mg daily on top of atorvastatin 10 mg daily who had undergone genetic analysis of ABCG5 or ABCG8 gene in our institute since 2006 to 2017. Pathogenicity of the variants were determined using standard variant filtering schema, including minor allele frequency, in silico annotation tools. Patients were divided into 2 groups based on the presence of ABCG5 or ABCG8 mutation. We compared the percent reduction of LDL cholesterol as well as the achieved LDL cholesterol levels between these 2 groups.

Results

We found 26 (8%) individuals who exhibit deleterious mutations in ABCG5 or ABCG8 gene. Baseline characteristics under the atorvastatin 10 mg therapy were comparable in age, gender, and LDL cholesterol level between 2 groups. Under these conditions, percent reduction of LDL cholesterol in mutation positive group was significantly larger than that of mutation negative group (28 ± 16% vs. 39 ± 21%, p < 0.05). As a result, the achieved LDL cholesterol level in mutation positive group was significantly lower than that of mutation negative group (87 ± 29 mg/dl vs. 72 ± 26% mg/dl, p < 0.05).

Conclusion

These results suggest that ezetimibe-atorvastatin combination therapy might be more beneficial in hypercholesterolemic patients with a mutation in ABCG5 or ABCG8 gene.

Reference Intervals of Serum Non-Cholesterol Sterols by Gender in Healthy Japanese Individuals

AIMS

The present study was conducted to establish a practical method for measuring non-cholesterol sterols and reference intervals of serum levels.

METHODS

Healthy subjects (109 men and 151 women), four patients with sitosterolemia, and 10 heterozygous mutation carriers of ABCG5/ABCG8 genes were investigated. Then, three non-cholesterol sterols (sitosterol, campesterol, and lathosterol) of fasting serum samples were measured via a practical and highly sensitive gas chromatography (GC) method with 0.2 µg/mL as the lower limit of quantification. The coefficient of variation (CV) values for within-run reproducibility were 3.06%, 1.89%, and 1.77% for lathosterol, campesterol, and sitosterol, respectively. The CV values for between-run reproducibility were 2.81%, 2.06%, and 2.10% for lathosterol, campesterol, and sitosterol, respectively.

RESULTS

The serum levels of sitosterol and campesterol were significantly higher in women than in men, whereas the serum levels of lathosterol were significantly higher in men than in women. Because of these gender difference, the determination of reference intervals of the three sterol values was performed by considering gender. The reference intervals of sitosterol, campesterol, and lathosterol were 0.99-3.88, 2.14-7.43, and 0.77-3.60 µg/mL in men and 1.03-4.45, 2.19-8.34, and 0.64-2.78 µg/mL in women, respectively. The serum levels of sitosterol and campesterol were higher in patients with sitosterolemia (94.3±47.3 and 66.3±36.6 µg/mL, respectively) than in healthy subjects.

CONCLUSION

These results demonstrate a practical and highly sensitive GC method to measure non-cholesterol sterol levels and gender-segregated reference intervals of sitosterol, campesterol, and lathosterol in Japanese healthy subjects.

Polyunsaturated Fatty Acid Impact on Clinical Outcomes in Acute Coronary Syndrome Patients With Dyslipidemia: Subanalysis of HIJ-PROPER

Background

This study aimed to examine the impact of baseline eicosapentaenoic acid (EPA) to arachidonic acid (AA) ratio on clinical outcomes of patients with acute coronary syndrome.

Methods and Results

In the HIJ‐PROPER (Heart Institute of Japan Proper Level of Lipid Lowering With Pitavastatin and Ezetimibe in Acute Coronary Syndrome) study, 1734 patients with acute coronary syndrome and dyslipidemia were randomly assigned to pitavastatin+ezetimibe therapy or pitavastatin monotherapy. We divided the patients into 2 groups based on EPA/AA ratio on admission (cutoff 0.34 μg/mL as median of baseline EPA/AA ratio) and examined their clinical outcomes. The primary end point comprised all‐cause death, nonfatal myocardial infarction, nonfatal stroke, unstable angina pectoris, or ischemia‐driven revascularization. Percentage reduction of low‐density lipoprotein cholesterol and triglyceride from baseline to follow‐up was similar regardless of baseline EPA/AA ratio. Despite the mean low‐density lipoprotein cholesterol level during follow‐up being similar between the low‐ and high‐EPA/AA groups, the mean triglyceride levels during follow‐up were significantly higher in the low‐ than in the high‐EPA/AA group. After 3 years of follow‐up, the cumulative incidence of the primary end point in patients with low EPA/AA was 27.2% in the pitavastatin+ezetimibe group compared with 36.6% in the pitavastatin‐monotherapy group (hazard ratio 0.69; 95% CI, 0.52‐0.93; P=0.015). However, there was no effect of pitavastatin+ezetimibe therapy on the primary end point in patients with high EPA/AA (hazard ratio 0.92; 95% CI, 0.70‐1.20; P=0.52).

Conclusions

Among acute coronary syndrome patients who have dyslipidemia and low EPA/AA ratio, adding ezetimibe to statin decreases the risk of cardiovascular events compared with statin monotherapy.

Clinical Trial Registration

URL: http://www.umin.ac.jp/ctr. Unique identifier: UMIN000002742

Low serum lathosterol levels associate with fatal cardiovascular disease and excess all-cause mortality: a prospective cohort study

IMPORTANCE

A more precise identification of patients at "high cardiovascular risk" is preeminent in cardiovascular risk stratification.

OBJECTIVE

To investigate the relationships between markers of cholesterol homeostasis, cardiovascular events and all-cause mortality.

DESIGN, SETTING AND PARTICIPANTS

We quantified markers of cholesterol homeostasis by gas chromatography-mass spectrometry in 377 subjects with suspected coronary artery disease, who were not on lipid-lowering drugs at baseline. All patients were followed for occurrence of cardiovascular events and mortality over a period of 4.9 +/- 1.7 years. The standardized mortality ratio (SMR) was calculated as the ratio of the observed and the expected deaths based on the death rates of the Regional Databases Germany, and Poisson regression (rate ratio, RR) was used to compare subgroups. The SMR and RR were standardized for sex, age category and calendar period. In addition, Cox regression (Hazard ratio, HR) was used to determine the effect of co-variables on (cardiovascular) mortality within the cohort.

MAIN OUTCOMES

Cardiovascular events, cardiovascular mortality and all-cause mortality.

RESULTS

A total of 42 deaths were observed in 1818 person-years corresponding with an SMR of 0.99 (95% CI 0.71-1.33; p = 0.556). A fatal cardiovascular event occurred in 26 patients. Lower levels of lathosterol were associated with increased cardiovascular mortality (HR 1.59; 95% CI: 1.16-2.17; p = 0.004) and excess all-cause mortality (HR 1.41; 95% CI: 1.09-1.85; p = 0.011). Lower lathosterol tertile compared to the adjacent higher tertile was associated with 1.6 times higher all-cause mortality risk (RR 1.60; 95% CI 1.07-2.40; p for trend = 0.022). This corresponded with a 2.3 times higher mortality risk of a lathosterol-LDL ratio equal to or below the median (RR 2.29; 95% CI 1.19-4.43; p = 0.013). None of the other cholesterol homeostasis markers were associated with cardiovascular and all-cause mortality.

CONCLUSIONS

In patients not on lipid-lowering agents, low serum lathosterol correlated with increased risk of cardiovascular events and excess all-cause mortality.

The emerging concept of "individualized cholesterol-lowering therapy": A change in paradigm

High LDL-cholesterol concentrations constitute a risk for atherosclerotic cardiovascular disease. By consensus, cholesterol-lowering therapy is initiated with a statin that reduces endogenous cholesterol synthesis, upregulates hepatic LDL receptor activity, increases LDL clearance and lowers LDL-cholesterol concentrations in the bloodstream. The efficacy of statin treatment is dose dependent and achieves a risk reduction of up to 50%. However, a substantial body of evidence suggests that a quarter of statin-treated patients do not respond adequately as a result of low endogenous cholesterol synthesis. In humans fractional cholesterol absorption varies from 20% to 80%. High cholesterol absorbers, which are characterized by a low-to-normal cholesterol synthesis, exhibit poor responsiveness to statin treatment. On the other hand, the cholesterol absorption inhibitor ezetimibe effectively reduces serum cholesterol levels in these patients. On this background, we suggest to "get personal" and individualize cholesterol-lowering therapies, according to the individual's status of cholesterol synthesis and absorption.

Ezetimibe for the prevention of cardiovascular disease and all-cause mortality events

BACKGROUND

Cardiovascular disease (CVD) remains an important cause of mortality and morbidity, and high levels of blood cholesterol are thought to be the major modifiable risk factors for CVD. The use of statins is the preferred treatment strategy for the prevention of CVD, but some people at high-risk for CVD are intolerant to statin therapy or unable to achieve their treatment goals with the maximal recommended doses of statin. Ezetimibe is a selective cholesterol absorption inhibitor, whether it has a positive effect on CVD events remains uncertain. Results from clinical studies are inconsistent and a thorough evaluation of its efficacy and safety for the prevention of CVD and mortality is necessary.

OBJECTIVES

To assess the efficacy and safety of ezetimibe for the prevention of CVD and all-cause mortality.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase and Web of Science on 27 June 2018, and two clinical trial registry platforms on 11 July 2018. We checked reference lists from primary studies and review articles for additional studies. No language restrictions were applied.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared ezetimibe versus placebo or ezetimibe plus other lipid-modifying drugs versus other lipid-modifying drugs alone in adults, with or without CVD, and which had a follow-up of at least 12 months.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data, assessed risk of bias and contacted trialists to obtain missing data. We performed statistical analyses according to the Cochrane Handbook for Systematic Reviews of Interventions and used the GRADE to assess the quality of evidence.

MAIN RESULTS

We included 26 RCTs randomising 23,499 participants. All included studies assessed effects of ezetimibe plus other lipid-modifying drugs compared with other lipid-modifying drugs alone or plus placebo. Our findings were driven by the largest study (IMPROVE-IT), which had weights ranging from 41.5% to 98.4% in the different meta-analyses.Ezetimibe with statins probably reduces the risk of major adverse cardiovascular events compared with statins alone (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.90 to 0.98; a decrease from 284/1000 to 267/1000, 95% CI 256 to 278; 21,727 participants; 10 studies; moderate-quality evidence). Trials reporting all-cause mortality used ezetimibe with statin or fenofibrate and found they have little or no effect on this outcome (RR 0.98, 95% CI 0.91 to 1.05; 21,222 participants; 8 studies; high-quality evidence). Adding ezetimibe to statins probably reduces the risk of non-fatal myocardial infarction (MI) (RR 0.88, 95% CI 0.81 to 0.95; a decrease from 105/1000 to 92/1000, 95% CI 85 to 100; 21,145 participants; 6 studies; moderate-quality evidence) and non-fatal stroke (RR 0.83, 95% CI 0.71 to 0.97; a decrease 32/1000 to 27/1000, 95% CI 23 to 31; 21,205 participants; 6 studies; moderate-quality evidence). Trials reporting cardiovascular mortality added ezetimibe to statin or fenofibrate, probably having little or no effect on this outcome (RR 1.00, 95% CI 0.89 to 1.12; 19457 participants; 6 studies; moderate-quality evidence). The need for coronary revascularisation might be reduced by adding ezetimibe to statin (RR 0.94, 95% CI 0.89 to 0.99; a decrease from 196/1000 to 184/1000, 95% 175 to 194; 21,323 participants; 7 studies); however, no difference in coronary revascularisation rate was observed when a sensitivity analysis was limited to studies with a low risk of bias.In terms of safety, adding ezetimibe to statins may make little or no difference in the risk of hepatopathy (RR 1.14, 95% CI 0.96 to 1.35; 20,687 participants; 4 studies; low-quality evidence). It is uncertain whether ezetimibe increase or decrease the risk of myopathy (RR 1.31, 95% CI 0.72 to 2.38; 20,581 participants; 3 studies; very low-quality evidence) and rhabdomyolysis, given the wide CIs and low event rate. Little or no difference in the risk of cancer, gallbladder-related disease and discontinuation due to adverse events were observed between treatment groups. For serum lipids, adding ezetimibe to statin or fenofibrate might further reduce the low-density lipoprotein cholesterol (LDL-C), total cholesterol and triglyceride levels and likely increase the high-density lipoprotein cholesterol levels; however, substantial heterogeneity was detected in most analyses.None of the included studies reported on health-related quality of life.

AUTHORS' CONCLUSIONS

Moderate- to high-quality evidence suggests that ezetimibe has modest beneficial effects on the risk of CVD endpoints, primarily driven by a reduction in non-fatal MI and non-fatal stroke, but it has little or no effect on clinical fatal endpoints. The cardiovascular benefit of ezetimibe might involve the reduction of LDL-C, total cholesterol and triglycerides. There is insufficient evidence to determine whether ezetimibe increases the risk of adverse events due to the low and very low quality of the evidence. The evidence for beneficial effects was mainly obtained from individuals with established atherosclerotic cardiovascular disease (ASCVD, predominantly with acute coronary syndrome) administered ezetimibe plus statins. However, there is limited evidence regarding the role of ezetimibe in primary prevention and the effects of ezetimibe monotherapy in the prevention of CVD, and these topics thus requires further investigation.