Statin therapy and plasma vitamin E concentrations: A systematic review and meta-analysis of randomized placebo-controlled trials

BACKGROUND: 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 I(2) 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

Statin therapy and plasma free fatty acids: a systematic review and meta-analysis of controlled clinical trials.

AIM: The aim of this meta-analysis was to evaluate the effect of statin therapy on plasma FFA concentrations in a systematic review and meta-analysis of controlled clinical trials. METHODS: PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched (from inception to February 16 2015) to identify controlled trials evaluating the impact of statins on plasma FFA 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 14 treatment arms indicated a significant reduction in plasma FFA concentrations following treatment with statins (weighted mean difference (WMD) -19.42%, 95% CI -23.19, --15.64, P < 0.001). Subgroup analysis confirmed the significance of the effect with both atorvastatin (WMD -20.56%, 95% CI -24.51, -16.61, P < 0.01) and simvastatin (WMD -18.05%, 95% CI -28.12, -7.99, P < 0.001). Changes in plasma FFA concentrations were independent of treatment duration (slope -0.10, 95% CI -0.30, 0.11, P = 0.354) and magnitude of reduction in plasma low density lipoprotein cholesterol concentrations (slope 0.55, 95% CI -0.17, 1.27, P = 0.133) by statins. CONCLUSIONS: The results of the present study suggest that statin therapy may lower plasma FFA concentrations. The cardiovascular and metabolic significance of this finding requires further investigation

The association of triglyceride and glucose index, and triglyceride to high‐density lipoprotein cholesterol ratio with prehypertension and hypertension in normoglycemic subjects: A large cross‐sectional population study

Insulin resistance (IR) plays an important role in the development of hypertension. Triglyceride and glucose index (TyG index), and triglyceride to high‐density lipoprotein cholesterol ratio (TG/HDL‐c) as effective IR surrogate indexes have been verified in numerous studies. Therefore, the authors conducted a large cross‐sectional study to explore the association of TyG index and TG/HDL‐c with prehypertension and hypertension in the same normoglycemic subjects from Tianjin, China. A total of 32 124 adults were eligible for this study. According to the level of blood pressure, the enrolled individuals were divided into three groups, which were normotension, prehypertension, and hypertension. In multiple logistic regression analysis, there was associated with prehypertension and hypertension when comparing the highest TyG index to the lowest TyG index and corresponding ORs were 1.795 (1.638, 1.968) and 2.439 (2.205, 2.698), respectively. For TG/HDL‐c, the corresponding ORs were 1.514 (1.382, 1.658) and 1.934 (1.751, 2.137), respectively. Furthermore, when comparing the fourth quartile to the first quartile of TyG index and TG/HDL‐c, respectively, both corresponding ORs of hypertension were higher than prehypertension. Elevated TyG index and TG/HDL‐c levels were associated with prehypertension and hypertension in normoglycemic individuals. Moreover, the TyG index was more significant than TG/HDL‐c in distinguishing hypertension. They have the potential to become cost‐effective monitors in the hierarchical management of prehypertension and hypertension