Does PPARγ2 gene Pro12Ala polymorphism affect nonalcoholic fatty liver disease risk? Evidence from a meta-analysis

Pulse wave velocity as a measure of arterial stiffness in patients with familial hypercholesterolemia: a systematic review and meta-analysis

INTRODUCTION

The aim of this meta-analysis was to establish whether vascular pulse wave velocity (PWV) as a measure of arterial stiffness is changed in patients with familial hypercholesterolemia (FH).

MATERIAL AND METHODS

Studies comparing PWV between patients with FH and controls were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (up to November 26, 2017). A meta-analysis was conducted using Comprehensive Meta-Analysis V2 software. A random-effects model (using the DerSimonian-Laird method) and the generic inverse variance method were used to compensate for the heterogeneity of studies concerning demographic characteristics and differences in the studies' design.

RESULTS

This meta-analysis of 8 studies involving 317 patients with FH and 244 non-FH individuals did not suggest a significantly altered PWV in FH patients versus controls (weighted mean difference (WMD): 0.17 m/s, 95% confidence interval (CI): -0.31, 0.65, p = 0.489; I ² = 80.15%). The result was robust in the sensitivity analysis and its significance was not influenced after omitting each of the included studies from the meta-analysis. Subanalysis of 6 of these studies which had data on intima-media thickness (IMT) indicated an increased IMT in FH patients when compared with controls (WMD = 0.03 mm, 95% CI: 0.003, 0.06, p = 0.034; I ² = 48.95%). However, the effect size was sensitive to some of the included studies.

CONCLUSIONS

This meta-analysis suggests that FH patients do not have significantly altered PWV when compared with normocholesterolemic individuals. However, a subanalysis of studies in which IMT was measured indicated that IMT is increased in FH patients compared with controls.

Efficacy and safety of avocado-soybean unsaponifiables for the treatment of hip and knee osteoarthritis: A systematic review and meta-analysis of randomized placebo-controlled trials

OBJECTIVE

We performed a systematic review and meta-analysis from randomized controlled trials to examine the efficacy and safety of avocado-soybean unsaponifiables (ASU) in patients with hip or knee osteoarthritis (OA).

DATA SOURCES

Medline, SCOPUS, Web of Science, and Google Scholar databases were searched for randomized placebo-controlled trials.

STUDY SELECTION

Original studies were randomized placebo-controlled trials evaluating the effect of orally administered ASU on knee or hip OA symptoms using the Lequesne index, visual analog scale (VAS) and/or joint space width (JSW).

DATA EXTRACTION

Meta-analysis was conducted using a random-effects model and generic inverse variance method. Heterogeneity was tested using the I² statistic index.

DATA SYNTHESIS

Avocado-soybean unsaponifiables therapy had a significant reduction on pain by VAS assessment (weighted mean difference [WMD]: -9.64 mm, 95% CI: -17.43, -1.84; P = .02; I²  = 92%). A subanalysis according to the type of OA showed that ASU significantly decreased both VAS and Lequesne index in knee OA (WMD: -17.36, 95% CI: -25.91, -8.82; P < .0001; I²  = 87% and WMD: -2.33, 95% CI: -2.88, -1.78; P < .00001; I²  = 18%, respectively) but not in hip OA. Finally, ASU supplementation showed no significant differences for adverse events compared to placebo (relative risk: 1.02, 95% CI: 0.83, 1.25; P = .88; I²  = 0%).

CONCLUSION

Results of this meta-analysis suggest a beneficial effect of ASU treatment in symptomatic knee OA but not in hip OA. Additionally, adverse events were similar in patients receiving ASU therapy or placebo.

Impact of ursodeoxycholic acid on circulating lipid concentrations: a systematic review and meta-analysis of randomized placebo-controlled trials

Objective

The aim of this meta-analysis of randomized placebo-controlled trials was to examine whether ursodeoxycholic acid treatment is an effective lipid-lowering agent.

Methods

PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched in order to find randomized controlled trials evaluating the effect of ursodeoxycholic acid on lipid profile. A random-effect model and the generic inverse variance weighting method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A random-effects meta-regression model was performed to explore the association between potential confounders and the estimated effect size on plasma lipid concentrations.

Results

Meta-analysis of 20 treatment arms revealed a significant reduction of total cholesterol following ursodeoxycholic acid treatment (WMD: − 13.85 mg/dL, 95% CI: -21.45, − 6.25, p < 0.001). Nonetheless, LDL-C (WMD: -6.66 mg/dL, 95% CI: -13.99, 0.67, p = 0.075), triglycerides (WMD: − 1.42 mg/dL, 95% CI: -7.51, 4.67, p = 0.648) and HDL-C (WMD: -0.18 mg/dL, 95% CI: -5.23, 4.87, p = 0.944) were not found to be significantly altered by ursodeoxycholic acid administration. In the subgroup of patients with primary biliary cirrhosis, ursodeoxycholic acid reduced total cholesterol (WMD: − 29.86 mg/dL, 95% CI: -47.39, − 12.33, p = 0.001) and LDL-C (WMD: -37.27 mg/dL, 95% CI: -54.16, − 20.38, p < 0.001) concentrations without affecting TG and HDL-C.

Conclusion

This meta-analysis suggests that ursodeoxycholic acid therapy might be associated with significant total cholesterol lowering particularly in patients with primary biliary cirrhosis.

Risk Factor Patterns for Premature Versus Late-Onset Coronary Artery Disease in Iran: A Systematic Review and Meta-Analysis

Background:

There are few data regarding the risk factors of premature vs late-onset Coronary Artery Disease (CAD). This study systematically reviews these risk factors in Iranian people.

Methods:

Medline, Web of Science, Embase and SID (Scientific Information Database; www.sid.ir) databases were searched for studies comparing CAD risk factors in young and older patients in Iran. Data extracted and pooled odds ratio (OR) with 95% Confidence Interval (CI) for each risk factor were calculated. Publication bias was evaluated by Egger’s test.

Results:

Seven studies (9080 participants) were included in the meta-analysis; analysis was carried out independently for each risk factor. Smoking (Odds Ratio (OR): 2.57, 95% CI: 1.96-3.37; p=<0.001), family history of CAD (OR: 2.45: 95% CI, 1.44-4.15, p<0.001), opium abuse (OR: 2.44: 95% CI, 1.22-4.88; p=0.001) and hyperlipidaemia (OR: 1.4: 95% CI, 1.13-1.73; p=0.001) were more common in premature CAD compared with older CAD patients. In contrast, diabetes mellitus (OR: 0.54: 95% CI, 0.39-0.73; p=0.0001) and hypertension (OR: 0.36, 95% CI: 0.21-0.59; p<0.001) were less prevalent.

Conclusion:

Risk factors were significantly different between premature and late-onset CAD. Policies regarding smoking and opium cessation and controlling hyperlipidaemia may be useful for the prevention of premature CAD in Iran.

The Pro12Ala polymorphism in the PPAR-γ2 gene is not associated with an increased risk of NAFLD in Iranian patients with type 2 diabetes mellitus

BACKGROUND

The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily. Several studies have demonstrated a significant association between Pro12Ala polymorphism of the PPAR-γ2 gene and metabolic disorders. Therefore, this study aimed to evaluate the association of Pro12Ala polymorphism with increased risk of NAFLD in Iranian patients with type 2 diabetes mellitus.

METHODS

This cross-sectional study was performed on 145 healthy control subjects and 145 NAFLD patients with a history of type 2 diabetes. Pro12Ala polymorphism genotyping was performed using PCR-restriction fragment length polymorphism (RFLP) technique with the Bs1I restriction enzyme.

RESULTS

Our results demonstrated that CC and GG genotypes of Pro12Ala were found in the participants, but there was no statistically significant difference between NAFLD patients and healthy controls (P = 0.64 and χ2 = 0.21).

CONCLUSION

This study suggests that Pro12Ala polymorphism of the PPAR-γ2 gene cannot be considered as a risk factor for NAFLD in the Iranian population.

Effect of fenofibrate on plasma apolipoprotein C-III levels: a systematic review and meta-analysis of randomised placebo-controlled trials

OBJECTIVES

This meta-analysis of randomised placebo-controlled clinical trials aimed to assess the effect of fenofibrate on apolipoprotein C-III (apo C-III), a key regulator of triglyceride metabolism.

MATERIALS AND METHODS

Randomised placebo-controlled trials investigating the impact of fenofibrate treatment on apo C-III levels were searched in PubMed-Medline, Scopus, Web of Science and Google Scholar databases from inception to 18 August 2017. Quantitative data synthesis was determined by a random-effects model and generic inverse variance method. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate glycaemic parameter confounders.

RESULTS

Meta-analysis of 10 clinical trials involving 477 subjects showed fenofibrate therapy decreased apo C-III levels (weighted mean difference (WMD) -4.78 mg/dL, 95% CI -6.95 to -2.61, p<0.001; I²66.87%). Subgroup analysis showed that fenofibrate reduced plasma apo C-III concentrations in subgroups of trials with treatment durations of either <12 weeks (WMD -4.50 mg/dL, p=0.001) or ≥12 weeks (WMD: -4.73 mg/dL, p=0.009) and doses of fenofibrate <200 mg/day (WMD -6.33 mg/dL, p<0.001) and >200 mg/day (p=0.006), with no significant difference between the subgroups.

CONCLUSION

This meta-analysis found that fenofibrate therapy significantly decreases apo C-III levels, an effect evident with both short-term treatment and doses less than 200 mg/day.

Effect of Statin Therapy on Arterial Wall Inflammation Based on 18F-FDG PET/CT: A Systematic Review and Meta-Analysis of Interventional Studies

Aim. To evaluate by meta-analysis of interventional studies the effect of statin therapy on arterial wall inflammation. Background. Arterial exposure to low-density lipoprotein (LDL) cholesterol levels is responsible for initiation and progression of atherosclerosis and arterial wall inflammation. 18F-fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (18F-FDG PET/CT) has been used to detect arterial wall inflammation and monitor the vascular anti-inflammatory effects of lipid-lowering therapy. Despite a number of statin-based interventional studies exploring 18F-FDG uptake, these trials have produced inconsistent results. Methods. Trials with at least one statin treatment arm were searched in PubMed-Medline, SCOPUS, ISI Web of Knowledge, and Google Scholar databases. Target-to-background ratio (TBR), an indicator of blood-corrected 18F-FDG uptake, was used as the target variable of the statin anti-inflammatory activity. Evaluation of studies biases, a random-effects model with generic inverse variance weighting, and sensitivity analysis were performed for qualitative and quantitative data assessment and synthesis. Subgroup and meta-regression analyses were also performed. Results. Meta-analysis of seven eligible studies, comprising 10 treatment arms with 287 subjects showed a significant reduction of TBR following statin treatment (Weighted Mean Difference (WMD): −0.104, p = 0.002), which was consistent both in high-intensity (WMD: −0.132, p = 0.019) and low-to-moderate intensity statin trials (WMD: −0.069, p = 0.037). Statin dose/duration, plasma cholesterol and C-reactive protein level changes, and baseline TBR did not affect the TBR treatment response to statins. Conclusions. Statins were effective in reducing arterial wall inflammation, as assessed by 18F-FDG PET/CT imaging. Larger clinical trials should clarify whether either cholesterol-lowering or other pleiotropic mechanisms were responsible for this effect.

Association of PPARG Gene Polymorphisms Pro12Ala with Type 2 Diabetes Mellitus: A Meta-analysis

BACKGROUND

Previous studies suggested that the single nucleotide polymorphisms of Pro12Ala located within the PPARG gene were significantly associated with the T2DM. Recently, the genetic studies on Pro12Ala were conducted in the different ethnic groups and the results of each study were shown to be inconsistent. Moreover, the systematic review has not been updated since 2000.

OBJECTIVE

To further validate the risk of Pro12Ala for T2DM disease based on the genetic data.

METHODS

The genetic studies on the Pro12Ala in the T2DM were searched in the PubMed and PMC database from January 2000 to October 2017. The meta-analysis was conducted with the CMA software.

RESULTS

The meta-analysis collected 14 studies including 20702 cases and 36227 controls. The combined analysis of all studies found that Pro12Ala was shown to be significantly associated with T2DM and the Ala allele played the increasing risks for the disease. Nevertheless, publication bias was detected in the combined analysis. The subgroup analysis indicated that Pro12Ala was found to be significant in the Caucasian and Chinese population. There was no heterogeneity and publication bias in these two groups.

CONCLUSION

The meta-analysis confirmed the evidence that the Pro12Ala was the susceptible variant for the decreasing risks for the T2DM.

Impact of ezetimibe on plasma lipoprotein(a) concentrations as monotherapy or in combination with statins: a systematic review and meta-analysis of randomized controlled trials

The aim of this meta-analysis of randomized placebo-controlled clinical trials was to assess the effect of ezetimibe on plasma lipoprotein(a) concentrations. Only randomized placebo-controlled trials investigating the impact of ezetimibe treatment on cholesterol lowering that include lipoprotein(a) measurement were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (from inception to February 26th, 2018). A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on lipoprotein concentrations. This meta-analysis of data from 10 randomized placebo-controlled clinical trials (15 treatment arms) involving a total of 5188 (3020 ezetimibe and 2168 control) subjects showed that ezetimibe therapy had no effect on altering plasma Lp(a) concentrations (WMD: -2.59%, 95% CI: -8.26, 3.08, p = 0.370; I2 = 88.71%, p(Q) < 0.001). In the subgroup analysis, no significant alteration in plasma Lp(a) levels was observed either in trials assessing the impact of monotherapy with ezetimibe versus placebo (WMD: -4.64%, 95% CI: -11.53, 2.25, p = 0.187; I2 = 65.38%, p(Q) = 0.005) or in trials evaluating the impact of adding ezetimibe to a statin versus statin therapy alone (WMD: -1.04%, 95% CI: -6.34, 4.26, p = 0.700; I2 = 58.51%, p(Q) = 0.025). The results of this meta-analysis suggest that ezetimibe treatment either alone or in combination with a statin does not affect plasma lipoprotein(a) levels.

Searching for Factors Raising the Incidence of Metabolic Syndrome Among 45-60-Year-Old Women

Metabolic syndrome is an increasing health problem, whose pathogenesis may be associated with genetic factors. The main purpose of our study was to assess relationships between MetS and the presence of the FTO rs9939609, the MC4R rs17782313, and the PPAR-γ rs1801282 polymorphisms in 45-60-year-old women. The study included patients from the general population of the Westpomeranian Province (Poland). The mean age was 54.3 ± 4.2 years. The research procedure involved taking structured history, physical examination, anthropometric measurements, and collecting blood for biochemical and genetic analysis. The patients who met the diagnostic criteria for MetS constituted 38.35% of all participants (sample size: 425 patients). The comparison of blood biochemical parameters revealed numerous differences between the women with MetS and those from the control group. Genetic analysis demonstrated that the T allele of the FTO gene was a factor substantially decreasing the incidence of MetS in the study sample (ORT vs. A = 0.734; 95% CI: 0.555 - 0.970; p < 0.05). Other polymorphisms were not directly related to MetS incidence.

CONCLUSIONS

1. MetS-related abnormalities are widespread in the population of 45-60-year-old Polish women. Those most common are the elevated serum total cholesterol and LDL levels, increased insulin resistance and BMI scores, as well as visceral obesity. 2. No direct relationships were demonstrated between MetS and the gene polymorphisms analyzed in our study except for the FTO rs9939609, whose A allele and A/A genotype seemed to predispose to metabolic disorders.

Impact of fibrates on circulating cystatin C levels: a systematic review and meta-analysis of clinical trials

AIMS

To assess the effect of fibrates on circulating cystatin C levels.

MATERIAL AND METHODS

Clinical studies evaluating the effect of a fibrate on circulating cystatin C levels were searched in PubMed-Medline, SCOPUS, Web of Science, and Google Scholar databases. A random-effect model and generic inverse variance method were used for quantitative data synthesis, sensitivity analysis conducted using the leave-one-out method, and weighted random-effects meta-regression performed to evaluate potential confounders on cystatin C levels.

RESULTS

This meta-analysis of data from nine published studies (16 treatment arms) involved a total of 2195 subjects. In a single-arm analysis of clinical trials (without control group; eight studies comprising 14 treatment arms), fibrate therapy increased circulating cystatin C concentrations (WMD: 0.07 mg/dL, 95% CI: 0.04, 0.10, p < .001; I² = 82.66%). When the analysis was restricted to randomized controlled trials (four studies comprising six treatment arms), again elevation of circulating cystatin C levels was observed (WMD: 0.06 mg/L, 95% CI: 0.03, 0.09, p < .001; I² = 42.98%). Elevated cystatin C levels were only seen with fenofibrate and not with other fibrates.

CONCLUSIONS

The results suggest that fenofibrate treatment adversely affects cystatin C levels and might partially explain the limited efficacy of fenofibrate in reducing cardiovascular events. Key message Fenofibrate treatment adversely affects cystatin C levels and might partially explain the limited efficacy of fenofibrate in reducing cardiovascular events.

Effect of ursodeoxycholic acid on glycemic markers: A systematic review and meta-analysis of clinical trials

Ursodeoxycholic acid (UDCA) is widely used to treat liver diseases; however, its potential effect on metabolic parameters has been poorly investigated. Additionally, owing to divergent data, the objective of this meta-analysis was to evaluate the effect of UDCA on glycemic parameters in clinical trials. Clinical trials investigating the impact of UDCA treatment on glycemic markers were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (from inception to April 16, 2018). A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on glycemic parameters. Meta-analysis of seven studies comprising eight treatment arms revealed a significant reduction of fasting glucose levels following UDCA therapy (WMD: -3.30 mg/dL, 95% CI: -6.36, -0.24, p = 0.034; I² = 28.95%). Also, meta-analysis of two treatment arms indicated a significant reduction of glycated hemoglobin (HbA1c) concentrations (WMD: -0.41% mg/dL, 95% CI: -0.81, -0.01, p = 0.042; I² = 0%). Additionally, meta-analysis of four treatment arms also revealed a significant reduction in plasma insulin levels (WMD: -1.50 mg/dL, 95% CI: -2.81, -0.19, p = 0.025; I² = 67.90%) but not significant effect HOMA-IR (WMD: -0.20 mg/dL, 95% CI: -0.42, 0.01, p = 0.057; I² = 85.34%). Results of this meta-analysis showed that UDCA significantly reduces fasting plasma glucose, HbA1c, and insulin concentrations suggesting a positive impact on glucose homeostasis.

Improvement of endothelial function by pitavastatin: a meta-analysis

OBJECTIVE

Dyslipidemia is commonly associated with endothelial dysfunction and increased cardiovascular risk. Pitavastatin has been shown to reduce total and low-density lipoprotein cholesterol, to increase high-density lipoprotein (HDL)-cholesterol and improve HDL function. Furthermore, several trials explored its effects on flow-mediated dilation (FMD), as an index of endothelial function. The authors evaluated the effect of pitavastatin therapy on FMD.

METHODS

The authors performed a systematic review and meta-analysis of all clinical trials exploring the impact of pitavastatin on FMD. The search included PubMed-Medline, Scopus, ISI Web of Knowledge and Google Scholar databases. Quantitative data synthesis was performed using a random-effects model, with weighted mean difference (WMD) and 95% confidence interval (CI) as summary statistics.

RESULTS

Six eligible studies comprising 7 treatment arms were selected for this meta-analysis. Overall, WMD was significant for the effect of pitavastatin on FMD (2.45%, 95% CI: 1.31, 3.60, p < 0.001) and the effect size was robust in the leave-one-out sensitivity analysis.

CONCLUSION

This meta-analysis of all available clinical trials revealed a significant increase of FMD induced by pitavastatin.

Effect of fibrates on glycemic parameters: A systematic review and meta-analysis of randomized placebo-controlled trials

AIMS

The aim of this meta-analysis of randomized placebo-controlled clinical trials was to assess the effect of fibrates on glycemic parameters.

MATERIALS AND METHODS

Only randomized placebo-controlled trials investigating the impact of fibrate treatment on glucose homeostasis markers were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (from inception to April 11, 2017). A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on glycemic parameters.

RESULTS

This meta-analysis of data from 22 randomized placebo-controlled clinical trials involving a total of 11,402 subjects showed that fibrate therapy significantly decreased fasting plasma glucose (WMD: -0.28 mmol/L, 95% CI: -0.42, -0.14, p < 0.001), insulin levels (WMD: -3.87 pmol/L, 95% CI: -4.97, -2.78, p < 0.001) and insulin resistance (HOMA-IR, WMD: -1.09, 95% CI: -1.71, -0.47, p = 0.001), but with no effect on HbA1c (WMD: 0.01%, 95% CI: -0.18, 0.19, p = 0.955). All analyses were robust in the leave-one-out sensitivity analysis except for insulin levels that showed a non-significant result (WMD: -0.84 pmol/L, 95% CI: -6.36, 4.68, p = 0.766) following omission of one of the included trials.

CONCLUSION

This meta-analysis has shown that fibrate treatment significantly decreases fasting plasma glucose, insulin levels, and HOMA-IR indicating additional clinical therapeutic benefits.

Association between statin use and plasma D-dimer levels

D-dimers, specific breakdown fragments of cross-linked fibrin, are generally used as circulating markers of activated coagulation. Statins influence haemostatic factors, but their effect on plasma D-dimer levels is controversial. Therefore, the aim of this meta-analysis was to evaluate the association between statin therapy and plasma D-dimer levels. We searched PubMed, Web of Science, Cochrane Library, Scopus and EMBASE (up to September 25, 2014) to identify randomised controlled trials (RCTs) investigating the impact of statin therapy on plasma D-dimer levels. Two independent reviewers extracted data on study characteristics, methods and outcomes. Meta-analysis of data from nine RCTs with 1,165 participants showed a significant effect of statin therapy in reducing plasma D-dimer levels (standardised mean difference [SMD]: –0.988 µg/ml, 95 % confidence interval [CI]: –1.590 – –0.385, p=0.001). The effect size was robust in sensitivity analysis and omission of no single study significantly changed the overall estimated effect size. In the subgroup analysis, the effect of statins on plasma D-dimer levels was significant only in the subsets of studies with treatment duration ≥ 12 weeks (SMD: –0.761 µg/ml, 95 %CI: –1.163– –0.360; p< 0.001), and for lipophilic statins (atorvastatin and simvastatin) (SMD: –1.364 µg/ml, 95 % CI: –2.202– –0.526; p=0.001). Hydrophilic statins (pravastatin and rosuvastatin) did not significantly reduce plasma D-dimer levels (SMD: –0.237 µg/ml, 95 %CI: –1.140–0.665, p=0.606). This meta-analysis of RCTs suggests a decrease of plasma D-dimer levels after three months of statin therapy, and especially after treatment with lipophilic statins. Well-designed trials are required to validate these results.

Note: The review process for this paper was fully handled by Christian Weber, Editor in Chief.

Lipid-modifying effects of krill oil in humans: systematic review and meta-analysis of randomized controlled trials

Context

Some experimental and clinical trials have shown that krill oil, extracted from small red crustaceans, might be an effective lipid-modifying agent, but the evidence is not conclusive.

Objective

The effect of krill oil supplements on plasma lipid concentrations was assessed through a systematic review of the literature and a meta-analysis of available randomized controlled trials.

Data sources

PubMed and Scopus were searched up to March 25, 2016, to identify RCTs investigating the effect of krill oil supplements on plasma lipids.

Study selection

Randomized controlled trials that investigated the impact of at least 2 weeks of supplementation with krill oil on plasma/serum concentrations of at least one of the main lipid parameters (ie, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or triglycerides) and that reported sufficient information on plasma/serum lipid levels at baseline and at the end of study in both krill oil and control groups were eligible for inclusion.

Data extraction

Two reviewers independently extracted the following data: first author's name, year of publication, study location, study design, number of participants in the krill oil and control groups, dosage of krill oil, type of control allocation, treatment duration, demographic characteristics of study participants, and baseline and follow-up plasma concentrations of lipids. Effect size was expressed as the weighted mean difference (WMD) and 95% confidence interval (95%CI).

Results

Meta-analysis of data from 7 eligible trials (14 treatment arms) with 662 participants showed a significant reduction in plasma concentrations of low-density lipoprotein cholesterol (WMD, -15.52 mg/dL; 95%CI, -28.43 to -2.61; P = 0.018) and triglycerides (WMD, -14.03 mg/dL; 95%CI, -21.38 to -6.67; P < 0.001) following supplementation with krill oil. A significant elevation in plasma concentrations of high-density lipoprotein cholesterol was also observed (WMD, 6.65 mg/dL; 95%CI, 2.30 to 10.99; P = 0.003), while a reduction in plasma concentrations of total cholesterol did not reach statistical significance (WMD, -7.50 mg/dL; 95%CI, -17.94 to 2.93; P = 0.159).

Conclusion

Krill oil supplementation can reduce low-density lipoprotein cholesterol and triglycerides. Additional clinical studies with more participants are needed to assess the impact of krill oil supplementation on other indices of cardiometabolic risk and on the risk of cardiovascular outcomes.

The Effects of Tamoxifen on Plasma Lipoprotein(a) Concentrations: Systematic Review and Meta-Analysis

Introduction

Tamoxifen is a selective estrogen receptor modulator widely used in the treatment of breast cancer. Tamoxifen therapy is associated with lower circulating low-density lipoprotein cholesterol and increased triglycerides, but its effects on other lipids are less well studied.

Aims

We aimed to investigate the effect of tamoxifen on circulating concentrations of lipoprotein(a) [Lp(a)] through a meta-analysis of available randomized controlled trials (RCTs) and observational studies.

Methods

This study was registered in the PROSPERO database (CRD42016036890). Scopus, MEDLINE and EMBASE were searched from inception until 22 March 2016 to identify studies investigating the effect of tamoxifen on Lp(a) values in humans. Meta-analysis was performed using an inverse variance-weighted, random-effects model with standardized mean difference (SMD) as the effect size estimate.

Results

Meta-analysis of five studies with 215 participants suggested a statistically significant reduction of Lp(a) levels following tamoxifen treatment (SMD −0.41, 95% confidence interval −0.68 to −0.14, p = 0.003). This effect was robust in the sensitivity analysis.

Conclusions

Meta-analysis suggested a statistically significant reduction of Lp(a) levels following tamoxifen treatment. Further well-designed trials are required to validate these results.

Development of gene polymorphisms in meditators of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide, the morbidity of which closely correlates with diversity of ethnicity, minority, family and location. Its histology spans from simple steatosis, to nonalcoholic steatohepatitis, which ultimately results in fibrosis, cirrhosis and hepatocellular carcinoma. The accelerating prevalence of NAFLD is due to an incremental incidence of metabolic syndrome that is distinguished by dyslipidemia, glucose impairment, obesity, excessive oxidative stress and adipocytokine impairment. Additionally, the pathogenesis of NAFLD is thought to be a multifactorial and complicated disease associated with lifestyle habits, nutritional factors and genetics. However, the pathogenesis and underlying mechanism in the development of NAFLD caused by genetics remains unclear. People have been increasingly emphasizing on the relationship between NAFLD and gene polymorphisms in recent years, with the aim of having a comprehensive elucidation of associated gene polymorphisms influencing the pathogenesis of the disease. In the current article, the authors attempted to critically summarize the most recently identified gene polymorphisms from the facets of glucose metabolism, fatty acid metabolism, oxidative stress and related cytokines in NAFLD that contribute to promoting the progression of the disease.

Effects of quercetin supplementation on lipid profile: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

In spite of promising experimental findings, randomized controlled trials (RCTs) have yielded mixed results on the impact of quercetin supplementation on plasma lipid levels.

AIM

The present study aimed to quantify the effects of quercetin on plasma lipids using a meta-analysis of RCTs.

METHODS

A systematic literature search of Medline was conducted for RCTs that investigated the efficacy of quercetin supplementation on plasma lipids comprising total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for net changes in lipid concentrations using a random-effects model. Meta-regression analysis was conducted to assess the effect of quercetin dose and duration of supplementation as moderators on the calculated effect measures.

RESULTS

Five RCTs totaling 442 subjects (221 in the quercetin and 221 in the control group) fulfilled the eligibility criteria and selected for analyses. Combined estimate of effect size for the impact of quercetin on plasma LDL-C (WMD: 1.43 mg/dL, 95% CI: -0.92-3.78, p = 0.23), HDL-C (WMD: 0.26 mg/dL, 95% CI: -0.74-1.25, p = 0.61) and triglycerides (WMD: -9.42 mg/dL, 95% CI: -27.80-8.96, p = 0.32) was not statistically significant. However, a borderline significant but clinically non-relevant increase in total cholesterol was observed (WMD: 3.13 mg/dL, 95% CI: -0.01-6.27, p = 0.05). When the analysis was confined to the subgroups of studies with quercetin doses ≥500 mg/day and follow-up of ≥ 4 weeks, a significant increase in total cholesterol (WMD: 3.57 mg/dL, 95% CI: 0.21-6.92, p = 0.04) and a decline in triglycerides (WMD: -24.54 mg/dL, 95% CI: -33.09 to -15.99, p < 0.00001) was observed, but LDL-C and HDL-C concentrations remained unchanged (p > 0.05). Changes in plasma triglycerides, but not other indices of lipid profile, were significantly associated with quercetin dose (slope: -0.057; 95% CI: -0.103 to -0.010; p = 0.02) and duration of supplementation (slope: -5.314; 95% CI: -9.482 to -1.147; p = 0.01).

CONCLUSION

Available evidence from RCTs does not suggest any clinically relevant effect of quercetin supplementation on plasma lipids, apart from a significant reduction of triglycerides at doses above 50 mg/day.

Comparison of the effects of fibrates versus statins on plasma lipoprotein(a) concentrations: a systematic review and meta-analysis of head-to-head randomized controlled trials

BACKGROUND

Raised plasma lipoprotein(a) (Lp(a)) concentration is an independent and causal risk factor for atherosclerotic cardiovascular disease. Several types of pharmacological approaches are under evaluation for their potential to reduce plasma Lp(a) levels. There is suggestive evidence that statins and fibrates, two frequently employed lipid-lowering drugs, can lower plasma Lp(a). The present study aims to compare the efficacy of fibrates and statins in reducing plasma concentrations of Lp(a) using a meta-analysis of randomized head-to-head trials.

METHODS

Medline and Scopus databases were searched to identify randomized head-to-head comparative trials investigating the efficacy of fibrates versus statins in reducing plasma Lp(a) levels. Meta-analysis was performed using a random-effects model, with inverse variance weighted mean differences (WMDs) and 95% confidence intervals (CIs) as summary statistics. The impact of putative confounders on the estimated effect size was explored using random effects meta-regression.

RESULTS

Sixteen head-to-head comparative trials with a total of 1388 subjects met the eligibility criteria and were selected for this meta-analysis. Meta-analysis revealed a significantly greater effect of fibrates versus statins in reducing plasma Lp(a) concentrations (WMD, -2.70 mg/dL; 95% CI, -4.56 to -0.84; P = 0.004). Combination therapy with fibrates and statins had a significantly greater effect compared with statin monotherapy (WMD, -1.60 mg/dL; 95% CI, -2.93 to -0.26; P = 0.019) but not fibrate monotherapy (WMD, -1.76 mg/dL; 95% CI, -5.44 to +1.92; P = 0.349) in reducing plasma Lp(a) concentrations. The impact of fibrates versus statins in reducing plasma Lp(a) concentrations was not found to be significantly associated with treatment duration (P = 0.788).

CONCLUSIONS

Fibrates have a significantly greater effect in reducing plasma Lp(a) concentrations than statins. Addition of fibrates to statins can enhance the Lp(a)-lowering effect of statins.

Effects of supplementation with pomegranate juice on plasma C-reactive protein concentrations: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Pomegranate juice (PJ) has a high content of antioxidants and bioactive polyphenols, being widely used for its antioxidant, anti-inflammatory and chemopreventive effects.

PURPOSE

The objective of this meta-analysis consisted in investigating the impact of PJ on plasma C-reactive protein (CRP) concentrations.

METHODS

The search included SCOPUS, Medline and two Iranian bibliographic databases namely MagIran and Scientific Information Database (from inception to December 09, 2014) to identify prospective trials for investigating the impact of pomegranate preparations on serum concentrations of CRP. Two independent reviewers extracted data on study characteristics, methods and outcomes.

RESULTS

Among 427 participants in the selected studies, 216 were allocated to PJ groups, and 211 to control group. Meta-analysis of data from 5 eligible randomized controlled trials (RCTs) arms did not provide compelling evidence as to a significant CRP-lowering effect of supplementation with pomegranate juice (WMD: -0.22 mg/l, 95% CI: -0.45, 0.01, p = 0.061). The impact of pomegranate juice on plasma CRP levels was found to be independent of duration of supplementation (slope: 0.003; 95% CI: -0.005, 0.011; p = 0.444).

CONCLUSION

In conclusion, this meta-analysis of data from 5 prospective trials did not indicate a significant effect of PJ on plasma CRP levels, and this effect was independent of duration of supplementation.

Lipoprotein(a) Levels in Patients With Abdominal Aortic Aneurysm

Circulating markers relevant to the development of abdominal aortic aneurysm (AAA) are currently required. Lipoprotein(a), Lp(a), is considered a candidate marker associated with the presence of AAA. The present meta-analysis aimed to evaluate the association between circulating Lp(a) levels and the presence of AAA. The PubMed-based search was conducted up to April 30, 2015, to identify the studies focusing on Lp(a) levels in patients with AAA and controls. Quantitative data synthesis was performed using a random effects model, with standardized mean difference (SMD) and 95% confidence interval (CI) as summary statistics. Overall, 9 studies were identified. After a combined analysis, patients with AAA were found to have a significantly higher level of Lp(a) compared to the controls (SMD: 0.87, 95% CI: 0.41-1.33, P < .001). This result remained robust in the sensitivity analysis, and its significance was not influenced after omitting each of the included studies from the meta-analysis. The present meta-analysis confirmed a higher level of circulating Lp(a) in patients with AAA compared to controls. High Lp(a) levels can be associated with the presence of AAA, and Lp(a) may be a marker in screening for AAA. Further studies are needed to establish the clinical utility of measuring Lp(a) in the prevention and management of AAA.

Effect of sour tea (Hibiscus sabdariffa L.) on arterial hypertension: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Hibiscus sabdariffa L. is a tropical wild plant rich in organic acids, polyphenols, anthocyanins, polysaccharides, and volatile constituents that are beneficial for the cardiovascular system. Hibiscus sabdariffa beverages are commonly consumed to treat arterial hypertension, yet the evidence from randomized controlled trials (RCTs) has not been fully conclusive. Therefore, we aimed to assess the potential antihypertensive effects of H. sabdariffa through systematic review of literature and meta-analysis of available RCTs.

METHODS

The search included PUBMED, Cochrane Library, Scopus, and EMBASE (up to July 2014) to identify RCTs investigating the efficacy of H. sabdariffa supplementation on SBP and DBP values. Two independent reviewers extracted data on the study characteristics, methods, and outcomes. Quantitative data synthesis and meta-regression were performed using a fixed-effect model, and sensitivity analysis using leave-one-out method. Five RCTs (comprising seven treatment arms) were selected for the meta-analysis. In total, 390 participants were randomized, of whom 225 were allocated to the H. sabdariffa supplementation group and 165 to the control group in the selected studies.

RESULTS

Fixed-effect meta-regression indicated a significant effect of H. sabdariffa supplementation in lowering both SBP (weighed mean difference -7.58 mmHg, 95% confidence interval -9.69 to -5.46, P < 0.00001) and DBP (weighed mean difference -3.53 mmHg, 95% confidence interval -5.16 to -1.89, P < 0.0001). These effects were inversely associated with baseline BP values, and were robust in sensitivity analyses.

CONCLUSION

This meta-analysis of RCTs showed a significant effect of H. sabdariffa in lowering both SBP and DBP. Further well designed trials are necessary to validate these results.

Analgesic Efficacy and Safety of Curcuminoids in Clinical Practice: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Curcuminoids are natural products with potent anti-inflammatory and antioxidant properties. There have been a number of reports on the analgesic effects of curcuminoids in clinical trials, yet data have not been fully conclusive.

OBJECTIVES

To provide the highest level of evidence on the efficacy of curcuminoids in patients with painful conditions through meta-analysis of data from randomized controlled trials (RCTs).

METHODS

A systematic review and meta-analysis was conducted using data reported by RCTs. The primary efficacy measure was pain intensity or algofunctional status. Treatment effect was summarized with standardized mean difference (SMD) calculated from differences in means of pain measures between treatment and control groups using a random-effects model.

RESULTS

A total of eight RCTs met our inclusion criteria that included 606 randomized patients. Curcuminoids were found to significantly reduce pain (SMD: -0.57, 95% CI: -1.11 to -0.03, P = 0.04). This pain-relieving effect was found to be independent of administered dose and duration of treatment with curcuminoids, and was free from publication bias. Curcuminoids were safe and well tolerated in all evaluated RCTs.

CONCLUSION

Curcuminoids supplements may be a safe and effective strategy to improve pain severity, by warranting further rigorously conducted studies to define the long-term efficacy and safety.

Effect of statin therapy on plasma proprotein convertase subtilisin kexin 9 (PCSK9) concentrations: a systematic review and meta-analysis of clinical trials

AIMS

To evaluate the magnitude of the effect of statin therapy on plasma proprotein convertase subtilisin kexin 9 (PCSK9) levels through a systematic review and meta-analysis of clinical trials.

METHODS

A random-effects model (using DerSimonian-Laird method) and the generic inverse variance method were used for quantitative data synthesis. Heterogeneity was quantitatively assessed using the I(2) index. Sensitivity analyses were conducted using the one-study remove approach. Random-effects meta-regression was performed using an unrestricted maximum likelihood method to evaluate the association between statin-induced elevation of plasma PCSK9 concentrations with duration of treatment and magnitude of LDL cholesterol reduction.

RESULTS

A total of 15 clinical trials examining the effects of statin therapy on plasma PCSK9 levels were included. Meta-analysis of data from single-arm statin treatment arms [weighted mean difference (WMD) 40.72 ng/ml, 95% confidence interval (CI) 34.79, 46.65; p < 0.001] and randomized placebo-controlled trials (WMD 22.98 ng/ml, 95% CI 17.95, 28.01; p < 0.001) showed a significant increase in plasma PCSK9 concentrations after statin therapy, irrespective of the type of statin administered in either of the analyses (single-arm or randomized placebo-controlled trial). There was no significant elevation of plasma PCSK9 levels with statin/ezetimibe combination therapy compared with statin monotherapy (WMD 23.14 ng/ml, 95% CI -1.97, 48.25; p = 0.071); however, removal of one study in the meta-analysis yielded a significant result in the sensitivity analysis (WMD 31.41 ng/ml, 95% CI 7.86, 54.97; p = 0.009).

CONCLUSIONS

This meta-analysis suggests that statin therapy causes a significant increase in plasma PCSK9 concentrations.

Does statin therapy reduce plasma VEGF levels in humans? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The effect of statins on plasma concentrations of vascular endothelial growth factor (VEGF), the main angiogenic growth factor with pro-inflammatory and atherogenic properties, is controversial. A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to obtain a conclusive result in humans.

METHODS

PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched to identify RCTs investigating the impact of statins on plasma VEGF concentrations. A random-effects model and the generic inverse variance method were used for quantitative data synthesis. Meta-regression, sensitivity analysis and publication bias assessments were performed using standard methods.

RESULTS

Eight RCTs examining the effects of statins on plasma VEGF concentrations were included. Meta-analysis suggested a significant reduction of plasma VEGF levels following statin therapy (weighed mean difference: -19.88 pg/mL, 95% CI: -35.87, -3.89, p=0.015). VEGF reductions were observed in the subsets of trials with treatment durations ≥4 weeks (-19.54, -37.78, -1.30, p=0.036), LDL-C reductions ≥50 mg/dL (-28.59, -43.68, -13.50, p<0.001), lipophilic statins (-22.31, -40.65, -3.98, p=0.017), and diseased populations (-21.08, -39.97, -2.18, p=0.029), but not in the opposite subsets. Meta-regression also suggested a significant association between changes in plasma VEGF levels and LDL-C changes, treatment duration, but not molar dose of statins.

CONCLUSIONS

These results suggest a significant reduction in plasma VEGF concentrations following statin therapy. This effect depends on duration of treatment, LDL-lowering activity, lipophilicity of statins, and health status of studied individuals. Further RCTs are needed to explore if the VEGF reduction is implicated in the statin benefits on cardiovascular outcomes.

Statin therapy and plasma coenzyme Q10 concentrations--A systematic review and meta-analysis of placebo-controlled trials

Statin therapy may lower plasma coenzyme Q10 (CoQ10) concentrations, but the evidence as to the significance of this effect is unclear. We assessed the impact of statin therapy on plasma CoQ10 concentrations through the meta-analysis of available RCTs. The literature search included selected databases up to April 30, 2015. The meta-analysis was performed using either a fixed-effects or random-effect model according to I(2) statistic. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence interval (CI). The data from 8 placebo-controlled treatment arms suggested a significant reduction in plasma CoQ10 concentrations following treatment with statins (WMD: -0.44 μmol/L, 95%CI: -0.52, -0.37, p<0.001). The pooled effect size was robust and remained significant in the leave-one-out sensitivity analysis. Subgroup analysis suggested that the impact of statins on plasma CoQ10 concentrations is significant for all 4 types of statins studied i.e. atorvastatin (WMD: -0.41 μmol/L, 95%CI: -0.53, -0.29, p<0.001), simvastatin (WMD: -0.47 μmol/L, 95% CI: -0.61, -0.33, p<0.001), rosuvastatin (WMD: -0.49 μmol/L, 95%CI: -0.67, -0.31, p<0.001) and pravastatin (WMD: -0.43 μmol/L, 95%CI: -0.69, -0.16, p=0.001). Likewise, there was no differential effect of lipophilic (WMD: -0.43 μmol/L, 95%CI: -0.53, -0.34, p<0.001) and hydrophilic statins (WMD: -0.47 μmol/L, 95%CI: -0.62, -0.32, p<0.001). With respect to treatment duration, a significant effect was observed in both subsets of trials lasting <12 weeks (WMD: -0.51 μmol/L, 95%CI: -0.64, -0.39, p<0.001) and ≥12 weeks (WMD: -0.40 μmol/L, 95%CI: -0.50, -0.30, p<0.001). The meta-analysis showed a significant reduction in plasma CoQ10 concentrations following treatment with statins. Further well-designed trials are required to confirm our findings and elucidate their clinical relevance.

Effect of garlic on plasma lipoprotein(a) concentrations: A systematic review and meta-analysis of randomized controlled clinical trials

OBJECTIVES

Garlic can play an essential role in the prevention of atherosclerosis, but the research addressing the effect of garlic on the concentration of lipoprotein(a) [Lp(a)] has not been fully demonstrated. The aim of this study was to assess the effect of garlic on plasma Lp(a) concentrations through systematic review of literature and meta-analysis of available randomized controlled trials.

METHODS

The literature search included SCOPUS, PubMed-Medline, ISI Web of Science, and Google Scholar databases up to March 10, 2015 to identify randomized controlled trials investigating the effect of garlic on plasma Lp(a) concentrations. Two independent reviewers extracted data on study characteristics, methods, and outcomes. Overall, the effect of garlic on plasma Lp(a) levels was reported in six trials.

RESULTS

Meta-analysis did not suggest a significant alteration in plasma Lp(a) levels after garlic consumption (weighted mean difference [WMD] = 16.86%; 95% confidence interval, -4.59 to 38.31; P = 0.124). This result was robust in the leave-one-out sensitivity analysis. When the studies were categorized according to the duration of supplementation, there was no effect in the subgroup of trials lasting ≤12 wk (WMD = 2.01%; 95% CI, -14.67 to 18.68; P = 0.813) but a significant elevation of plasma Lp(a) concentrations was found in trials lasting >12 wk (WMD = 54.59%; 95% CI, 30.47-78.71; P < 0.001). Random-effects meta-regression suggested an inverse association between the changes in plasma concentrations of Lp(a) and duration of supplementation (slope 1.71; 95% CI, 0.46-2.97; P = 0.007).

CONCLUSIONS

The present meta-analysis did not suggest a significant effect of garlic supplementation on the reduction of Lp(a) levels.

A systematic review and meta-analysis of the effect of statins on plasma asymmetric dimethylarginine concentrations

The impact of statin therapy on plasma asymmetric dimethylarginine (ADMA) levels has not been conclusively studied. Therefore the aim of the meta-analysis was to assess the effect of statins on circulating ADMA levels. We searched selected databases (up to August 2014) to identify randomized controlled trials (RCTs) that investigate the effect of statins on plasma ADMA concentrations. A weighted meta-regression (WMD) using unrestricted maximum likelihood model was performed to assess the impact of statin dose, duration of statin therapy and baseline ADMA concentrations as potential variables on the WMD between statin and placebo group. In total, 1134 participants in 9 selected RCTs were randomized; 568 were allocated to statin treatment and 566 were controls. There was a significant reduction in plasma ADMA concentrations following statin therapy compared with placebo (WMD: − 0.104 μM, 95% confidence interval: − 0.131 to − 0.077, Z = − 7.577, p < 0.0001). Subgroups analysis has shown a significant impact of hydrophilic statins (WMD: − 0.207 μM, 95%CI: − 0.427 to + 0.013, Z = − 7.250, p < .0001) and a non-significant effect of hydrophobic statins (WMD: − 0.101 μM, 95%CI: − 0.128 to − 0.074, Z = − 1.845, p = 0.065). In conclusion, this meta-analysis of available RCTs showed a significant reduction in plasma ADMA concentrations following therapy with hydrophilic statins.

Lipid profile and glucose changes after supplementation with astaxanthin: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Many studies have shown that oral supplementation with astaxanthin may be a novel potential treatment for inflammation and oxidative stress in cardiovascular diseases, but evidence of the effects on lipid profile and glucose is still inconclusive. Therefore, we performed a meta-analysis to evaluate the efficacy of astaxanthin supplementation on plasma lipid and glucose concentrations.

MATERIAL AND METHODS

The search included PubMed, Cochrane Library, Scopus, and EMBASE (up to November 27, 2014) to identify randomized controlled trials (RCTs) investigating the effects of astaxanthin supplementation on lipid profile and glucose levels. Two independent reviewers extracted data on study characteristics, methods and outcomes.

RESULTS

Seven studies meeting inclusion criteria with 280 participants were selected for this meta-analysis; 163 participants were allocated to the astaxanthin supplementation group and 117 to the control group. A random-effect meta-analysis of data from 7 RCTs (10 treatment arms) did not show any significant effect of supplementation with astaxanthin on plasma concentrations of total cholesterol (weighted mean difference (WMD): -1.52 mg/dl, 95% CI: -8.69 to -5.66, p = 0.679), LDL-C (WMD: +1.25 mg/dl, 95% CI: -6.70 to +9.21, p = 0.758), HDL-C (WMD: +1.75 mg/dl, 95% CI: -0.92 to +4.42, p = 0.199), triglycerides (WMD: -4.76 mg/dl, 95% CI: -21.52 to +12.00, p = 0.578), or glucose (WMD: -2.65 mg/dl, 95% CI: -5.84 to +0.54, p = 0.103). All these effect sizes were robust, and omission of any of the included studies did not significantly change the overall estimate.

CONCLUSIONS

This meta-analysis of data from 10 RCT arms did not indicate a significant effect of supplementation with astaxanthin on plasma lipid profile, but a slight glucose-lowering effect was observed. Further, well-designed trials are necessary to validate these results.

Lack of efficacy of resveratrol on C-reactive protein and selected cardiovascular risk factors--Results from a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Numerous studies have suggested that oral supplementation with resveratrol exerts cardioprotective effects, but evidence of the effects on C-reactive protein (CRP) plasma levels and other cardiovascular (CV) risk factors is inconclusive. Therefore, we performed a meta-analysis to evaluate the efficacy of resveratrol supplementation on plasma CRP concentrations and selected predictors of CV risk.

METHODS

The search included PUBMED, Cochrane Library, Web of Science, Scopus, and EMBASE (up to August 31, 2014) to identify RCTs investigating the effects of resveratrol supplementation on selected CV risk factors. Quantitative data synthesis was performed using a random-effects model, with weighted mean difference (WMD) and 95% confidence intervals (CI) as summary statistics.

RESULTS

Meta-analysis of data from 10 RCTs (11 treatment arms) did not support a significant effect of resveratrol supplementation in altering plasma CRP concentrations (WMD: -0.144 mg/L, 95% CI: -0.968-0.680, p = 0.731). Resveratrol supplementation was not found to alter plasma levels of total cholesterol (WMD: 1.49 mg/dL, 95% CI: -14.96-17.93, p = 0.859), low density lipoprotein cholesterol (WMD: -0.31 mg/dL, 95% CI: -9.57-8.95, p = 0.948), triglycerides (WMD: 2.67 mg/dL, 95% CI: -28.34-33.67, p = 0.866), and glucose (WMD: 1.28 mg/dL, 95% CI: -5.28-7.84, p = 0.703). It also slightly reduced high density lipoprotein cholesterol concentrations (WMD: -4.18 mg/dL, 95% CI: -6.54 to -1.82, p = 0.001). Likewise, no significant effect was observed on systolic (WMD: 0.82 mmHg, 95% CI: -8.86-10.50, p = 0.868) and diastolic blood pressure (WMD: 1.72 mm Hg, 95% CI: -6.29-9.73, p=0.674).

CONCLUSIONS

This meta-analysis of available RCTs does not suggest any benefit of resveratrol supplementation on CV risk factors. Larger, well-designed trials are necessary to confirm these results.

Impact of fibrate therapy on plasma plasminogen activator inhibitor-1: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The aim of this systematic review was to perform a meta-analysis of randomized controlled trials (RCTs) examining the efficacy of fibrate therapy in reducing plasma concentration or activity of plasminogen activator inhibitor 1 (PAI-1).

METHODS

Scopus and MEDLINE databases were searched (up to October 15, 2014) to identify RCTs investigating whether fibrates lower plasma PAI-1 concentration or activity. A random-effects model and the generic inverse variance method were used for quantitative data synthesis. Sensitivity analyses were conducted using the one-study remove approach. Random-effects meta-regression was performed to assess the impact of potential moderators on the estimated effect sizes.

RESULTS

A total of 14 RCTs examining the effects of gemfibrozil (6 trials), bezafibrate (4 trials), and fenofibrate (5 trials) were included. Meta-analysis suggested that fibrate therapy did not significantly reduce plasma PAI-1 concentration (weighed mean difference [WMD]: -11.39 ng/mL, 95% CI: -26.64, 3.85, p=0.143) or activity (WMD: 2.02 U/mL, 95% CI: -0.87, 4.90, p=0.170). These results remained unchanged after subgroup analysis according to duration of treatment (<12 and ≥12 weeks) and type of fibrate administered (fenofibrate, bezafibrate or gemfibrozil). The estimated effects of fibrate therapy on plasma concentration and activity of PAI-1 were independent of treatment duration and changes in plasma triglyceride levels in the meta-regression analysis.

CONCLUSION

This meta-analysis of RCTs suggested that fibrate therapy does not reduce plasma concentration or activity of PAI-I. The putative benefits of fibrate therapy in patients with cardiovascular disease appear to be exerted via mechanisms independent of effects on PAI-1.

Effect of L-carnitine Supplementation on Circulating C-reactive Protein Levels: A Systematic Review and Meta-Analysis

Background

C-reactive protein (CRP) has been proposed as a risk marker and risk factor of cardiovascular disease. There have been a number of clinical reports suggesting that supplementation with L-carnitine can modulate systemic inflammation and lower circulating CRP concentrations, but the results have not been consistent.

Methods

A comprehensive literature search in Medline, Scopus and Cochrane Central Register of Controlled Trials was performed in December 2012 to identify clinical trials investigating the impact of oral L-carnitine supplementation on serum/plasma CRP concentration. A random effect method was used to calculate the combined effect size.

Results

Six studies comprising 541 cases and 546 controls met the inclusion criteria. Meta-analysis of included trials revealed a significant reduction of circulating CRP concentrations in subjects under L-carnitine intervention compared to the control treatment. The calculated combined weighted mean reduction in CRP concentrations was −0.39 mg/L [95% CI (−0.62 – −0.16)]. This effect size estimate was found to be robust and remained unaffected by the removal of each single study.

Conclusions

The overall findings of the present meta-analysis support the clinically relevant benefit of L-carnitine supplementation in lowering the circulating levels of CRP.

Systematic review of genetic association studies involving histologically confirmed non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease has an increasing prevalence in Western countries, affecting up to 20% of the population.

Analysis of vitamin D levels in patients with and without statin-associated myalgia - a systematic review and meta-analysis of 7 studies with 2420 patients

INTRODUCTION

Vitamin D (vit D) deficiency may be associated with an increased risk of statin-related symptomatic myalgia in statin-treated patients. The aim of this meta-analysis was to substantiate the role of serum vitamin D levels in statin-associated myalgia.

METHODS

The search included PUBMED, Cochrane Library, Scopus, and EMBASE from January 1, 1987 to April 1, 2014 to identify studies that investigated the impact of vit D levels in statin-treated subjects with and without myalgia. Two independent reviewers extracted data on study characteristics, methods and outcomes. Quantitative data synthesis was performed using a fixed-effect model.

RESULTS

The electronic search yielded 437 articles; of those 20 were scrutinized as full texts and 13 studies were considered unsuitable. The final analysis included 7 studies with 2420 statin-treated patients divided into subgroups of patients with (n=666 [27.5%]) or without (n=1754) myalgia. Plasma vit D concentrations in the symptomatic and asymptomatic subgroups were 28.4±13.80ng/mL and 34.86±11.63ng/mL, respectively. The combination of data from individual observational studies showed that vit D plasma concentrations were significantly lower in patients with statin-associated myalgia compared with patients not manifesting this side effect (weighted mean difference -9.41ng/mL; 95% confidence interval: -10.17 to -8.64; p<0.00001).

CONCLUSIONS

This meta-analysis provides evidence that low vit D levels are associated with myalgia in patients on statin therapy. Randomized controlled trials are necessary to establish whether vitamin D supplementation reduces the risk for statin-associated myalgia.

Effect of niacin on endothelial function: a systematic review and meta-analysis of randomized controlled trials

Endothelial dysfunction is an independent predictor of incident atherosclerotic cardiovascular disease (ACVD). Niacin possesses high-density lipoprotein (HDL)-elevating, antioxidant and anti-inflammatory properties, all potentially contributing to the amelioration of endothelial function. However, controversies exist among trials reporting the effects of niacin on endothelium-dependent flow-mediated dilation (FMD) as a reliable surrogate of endothelial function. The objective of this study was to assess the effect of niacin on brachial artery FMD using a meta-analysis of available evidence. MEDLINE and Scopus databases were searched for randomized controlled trials investigating the impact of niacin therapy on brachial artery FMD. Meta-analysis of eligible studies was conducted using a random-effects model. Pooled effects were measured by weighted mean difference (WMD) and 95% confidence intervals (CIs). Quality assessment, and subgroup, meta-regression and sensitivity analyses were conducted using standard methods. Among 596 citations, 19 full-text articles were read and seven were found to be eligible for inclusion. Eligible studies involved 441 subjects comprising 228 in the niacin and 213 in the control groups. Niacin therapy significantly improved FMD (WMD: 1.98%; 95% CI: 0.91-3.05%; p = 0.0003) and this effect was robust in the sensitivity analysis. The effect size was greater in the subgroup of studies administering higher doses of niacin (≥ 2000 mg/day) as well as those studies administering niacin for primary prevention of ACVD. Meta-regression indicated no association between niacin-induced changes in FMD and changes in plasma HDL-cholesterol, low-density lipoprotein-cholesterol or triglycerides. None of the included studies could find any significant effect of niacin on nitroglycerin-mediated dilation. In conclusion, treatment with niacin improves endothelial function.