Analysis of quality of interventions in systematic reviews

摘要

Randomised controlled trials provide the best test of the efficacy of preventive or therapeutic interventions because they can separate the effects of the intervention from those of extraneous factors such as natural recovery and statistical regression. When more than one trial has examined a particular intervention, systematic reviews potentially provide the best summaries of the available evidence.Systematic reviewers can summarise findings of randomised trials using an impressionistic approach (qualitative synthesis) or they can produce quantitative syntheses by statistically combining the results from several studies (meta-analysis). Regardless of the method used, most systematic reviewers seek to reduce data from clinical trials into simple statements about treatment. Systematic reviews that provide succinct statements about the effects of an intervention are particularly useful to clinicians. But simple summaries are possible only when the studies address similar questions in similar ways.