1,720,961 research outputs found
A systematic review and meta-analysis of controlled trials on the effects of statin and fibrate therapies on plasma homocysteine levels.
No full textCurcumin Downregulates Human Tumor Necrosis Factor-α Levels: A systematic review and meta-analysis of randomized controlled trials.
No full textBackground Tumor necrosis factor-α (TNF-α) is a key inflammatory mediator and its reduction is a therapeutic target in several inflammatory diseases. Curcumin, a bioactive polyphenol from turmeric, has been shown in several preclinical studies to block TNF-α effectively. However, clinical evidence has not been fully conclusive. Objective The aim of the present meta-analysis was to evaluate the efficacy of curcumin supplementation on circulating levels of TNF-α in randomized controlled trials (RCTs). Methods The search included PubMed-Medline, Scopus, Web of Science and Google Scholar databases by up to September 21, 2015, to identify RCTs investigating the impact of curcumin on circulating TNF-α concentration. Quantitative data synthesis was performed using a random-effects model, with weighed mean difference (WMD) and 95% confidence interval (CI) as summary statistics. Meta-regression and leave-one-out sensitivity analyses were performed to assess the modifiers of treatment response. Results Eight RCTs comprising nine treatment arms were finally selected for the meta-analysis. There was a significant reduction of circulating TNF-α concentrations following curcumin supplementation (WMD: -4.69 pg/mL, 95% CI: -7.10, -2.28, p < 0.001). This effect size was robust in sensitivity analysis. Meta-regression did not suggest any significant association between the circulating TNF-α-lowering effects of curcumin with either dose or duration (slope: 0.197; 95% CI: -1.73, 2.12; p = 0.841) of treatment. Conclusion This meta-analysis of RCTs suggested a significant effect of curcumin in lowering circulating TNF-α concentration
Effects of orlistat on blood pressure: a systematic review and meta-analysis of 27 randomized controlled clinical trials.
No full textObesity and high blood pressure (BP) are strongly related and weight loss is mightily associated with a significant BP decrease. The aim of the present meta-analysis was to evaluate and quantify the BP decrease associated with orlistat use in randomized controlled trials. The search included PubMed-Medline, Scopus, Web of Science and Google Scholar databases by up to June 05, 2017, to identify randomized controlled trials investigating the impact of orlistat on blood pressure. Quantitative data synthesis was performed using a random-effects model, with weighed mean difference and 95% confidence interval as summary statistics. Meta-regression and leave-one-out sensitivity analyses were performed to assess the modifiers of treatment response. Our meta-analysis included 27 randomized controlled clinical trials which comprehended overall 8150 subjects (4419 in the orlistat group and 3731 in the control one). We observed a statistically significant decreasing effect of orlistat on both systolic BP (-1.15 mmHg [-2.11, -0.19]) and diastolic BP (-1.07 mmHg [-1.69, -0.45]), regardless of its dosage. Significant associations were found between changes in systolic BP and diastolic BP with treatment duration but not with corresponding baseline BP values. In conclusion, Orlistat use contributes weight loss associated decrease in BP in overweight and obese subjects
The Effects of a Nutraceutical Combination on Plasma Lipids and Glucose: a Systematic Review and Meta-Analysis of Randomized Controlled Trials
No full textDyslipidemia and hyperglycemia are associated with an increased risk of ischemic cardiovascular disease. Positive effects of a nutraceutical combination comprising red yeast rice, berberine, policosanol, astaxanthin, coenzyme Q10 and folic acid (NComb) on plasma lipid and glucose levels have been reported in some but not all clinical trials. To address this inconsistency, we tried to estimate the size of lipid- and glucose-lowering effects of NComb through a systematic review and meta-analysis of randomized controlled trials. A systematic literature search in PubMed-Medline, SCOPUS and Google Scholar databases was conducted to identify randomized controlled trials investigating the effects of NComb on plasma lipids and glucose levels. Inverse variance-weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for net changes in lipid and glucose levels using a random-effects model. Random-effects meta-regression was performed to assess the effect of putative confounders on plasma lipid and glucose levels. Fourteen trials (1670 subjects in the NComb arm and 1489 subjects in the control arm) met the eligibility criteria for lipid analysis and 10 trials (1014 subjects in the NComb arm and 962 subjects in the control arm) for glucose analysis. Overall, WMDs were significant for the impact of NComb supplementation on plasma levels of total cholesterol (-26.15mg/dL, p<0.001), LDL-cholesterol (-23.85mg/dL, p<0.001), HDL-cholesterol (2.53mg/dL, p<0.001), triglycerides (-13.83mg/dL, p<0.001) and glucose (-2.59mg/dL, p=0.010). NComb-induced amelioration of lipid profile was not affected by duration of supplementation nor by baseline lipid levels; conversely, a greater glucose-lowering effect of NComb was found with higher baseline glucose levels and longer durations of supplementation. In conclusion, the present results suggest that NComb supplementation is associated with improvement of lipid and glucose profile. Short-term beneficial effects of NComb supplementation appear to be maintained in the long term
A Systematic Review and Meta-Analysis of Controlled Trials on the Effects of Statin and Fibrate Therapies on Plasma Homocysteine Levels.
No full textBackground: Plasma homocysteine is an independent non-traditional risk factor for atherosclerotic cardiovascular disease. The impact of statin therapy on plasma homocysteine is not conclusive. Objective: To evaluate the effect of statin therapy on plasma homocysteine concentrations in a systematic review and meta-analysis of controlled clinical trials. The secondary aim was to assess the comparative effect of statins versus fibrates on plasma homocysteine levels in head-to-head trials. Method: PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched (from the first reports to March 07, 2016) to identify controlled trials evaluating the impact of statins on plasma homocysteine concentrations. A systematic assessment of bias in the included studies was performed using the Cochrane criteria. 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. Random-effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential moderators. Results: Meta-analysis of data from 7 studies did not suggest a significant alteration in plasma homocysteine concentrations following treatment with statins compared with the control group (WMD: -0.59 μmol/L, 95% CI: -1.66, 0.48, p=0.279; I2=52.53%). However, meta-analysis of 9 studies suggested a significantly greater reduction of plasma homocysteine concentrations with statins compared with fenofibrate (WMD: -4.81 μmol/L, 95% CI: -5.39, -4.23, p<0.001; I2=0%). Results of both analyses were robust in the sensitivity analysis. Conclusion: Statin therapy is not associated with a significant alteration of plasma homocysteine levels, while fenofibrate increases the homocysteine levels when compared with statins
Statin therapy and plasma vitamin E concentrations: a systematic review and meta-analysis of randomized placebo-controlled trials
No full textBackground: Vitamin E is one of the most important natural antioxidants, and its plasma levels are inversely associated with the progression of atherosclerosis. There have been reports suggesting a potential negative effect of statin therapy on plasma vitamin E levels. The aim of this meta-analysis was to determine the impact of statin therapy on plasma vitamin E concentrations.
Methods: PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched to identify randomized placebo-controlled trials evaluating the impact of statins on plasma vitamin E concentrations from inception to February 27, 2015. A systematic assessment of bias in the included studies was performed using the Cochrane criteria. A random-effects model (using DerSimonian-Laird method) and the generic inverse variance method were used to examine the effect of statins on plasma vitamin E concentrations. Heterogeneity was quantitatively assessed using the I2 index. Sensitivity analysis was conducted using the leave-one-out method.
Results: A meta-analysis of data from 8 randomized treatment arms including 504 participants indicated a significant reduction in plasma vitamin E concentrations following statin treatment (WMD: −16.30%, 95% CI: −16.93, −15.98, p < 0.001). However, cholesterol-adjusted vitamin E concentrations (defined as vitamin E:total cholesterol ratio) were found to be improved by statin therapy (WMD: 29.35%, 95% CI: 24.98, 33.72, p < 0.001). Statin therapy was not associated with any significant alteration in LDL vitamin E content (SMD: 0.003, 95% CI: −0.90, 0.90, p = 0.995).
Conclusion: Findings of the present study suggest that statin therapy has no negative impact on plasma vitamin E concentrations or LDL vitamin E content
Effect of extended-release niacin on plasma Lipoprotein(a) levels: a systematic review and meta-analysis of randomized placebo-controlled trials.
No full textAIM:
Lipoprotein(a) (Lp(a)) is a proatherogenic and prothrombotic lipoprotein. Our aim was to quantify the extended-release nicotinic acid Lp(a) reducing effect with a meta-analysis of the available randomized clinical trials.
METHODS:
A meta-analysis and random-effects meta-regression were performed on data pooled from 14 randomized placebo-controlled clinical trials published between 1998 and 2015, comprising 17 treatment arms, which included 9013 subjects, with 5362 in the niacin arm.
RESULTS:
The impact of ER niacin on plasma Lp(a) concentrations was reported in 17 treatment arms. Meta-analysis suggested a significant reduction of Lp(a) levels following ER niacin treatment (weighted mean difference - WMD: -22.90%, 95% CI: -27.32, -18.48, p<0.001). Results also remained similar when the meta-analysis was repeated with standardized mean difference as summary statistic (WMD: -0.66, 95% CI: -0.82, -0.50, p<0.001). When the studies were categorized according to the administered dose, there was a comparable effect between the subsets of studies with administered doses of <2000mg/day (WMD: -21.85%, 95% CI: -30.61, -13.10, p<0.001) and ≥2000mg/day (WMD: -23.21%, 95% CI: -28.41, -18.01, p<0.001). The results of the random-effects meta-regression did not suggest any significant association between the changes in plasma concentrations of Lp(a) with dose (slope: -0.0001; 95% CI: -0.01, 0.01; p=0.983), treatment duration (slope: -0.40; 95% CI: -0.97, 0.17; p=0.166), and percentage change in plasma HDL-C concentrations (slope: 0.44; 95% CI: -0.48, 1.36; p=0.350).
CONCLUSION:
In this meta-analysis of randomized placebo-controlled clinical trials, treatment with nicotinic acid was associated with a significant reduction in Lp(a) levels
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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