[Clinical trials of statins and fibrates --a meta-analysis].
Several clinical trials of hypolipidemics showed a decrease in mortality by 30-40%, while others showed detrimental or no effects. The question remains: which trial should be the basis of clinical decision making in the choice of hypolipidemic therapy? Meta-analysis is a method for combining research results of several studies. Effects of statins and fibrates with respect to placebo, were assessed by systematic literature review and meta-analysis. Medline and CENTRAL databases were searched using the following keywords: hyperlipoproteinemia, hypolipidemic agents and individual drug names. The main inclusion criteria were as follows: statin or fibrate, placebo controlled randomized trial, at least one year treatment on average, at least 100 patients per study arm and reported mortality. Fibrates showed almost complete absence of treatment effects on mortality with odds ratio of 0.99 and 95% confidence interval 0.80 - 1.11. The odds for statins were 0.87, 0.80 - 0.95. Despite the absence of treatment effects of fibrates, it is noteworthy that inclusion criteria of early fibrate trials focused mainly on cholesterol with recent identification of elevated triglycerides as an independent risk factor. As fibrates exert the most pronounced effect on triglycerides, they still may show effect in target populations. Effects of statins are confirmed, but they are noticeably lower than in individual trials which are given most publicity. Even after several decades of fibrate use, conclusive evidence of their beneficial effects still needs to be elucidated in appropriately designed trials. However, a beneficial effect of statins on mortality decrease has been proven. Meta-analysis has an important role in estimating true treatment effects and in the practice of evidence-based medicine.