Seminars in reproductive medicine
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Semin. Reprod. Med. · Feb 2003
ReviewRandomized clinical trials: the meeting place of medical practice and clinical research.
Randomized clinical trials (RCTs) have been used to assess interventions affecting health since biblical times. They provide the most valid means of measuring the true effects of intervention compared with no treatment or placebo. Although they can also be used to assess the value of diagnostic tests, this article focuses on randomized trials in the context of treatment. ⋯ It is also essential to establish that the question posed is ethical, the methods of study are valid, and that follow-up is complete, with an "intent to treat" analysis. Results are best presented using both proportions and absolute numbers. By providing clinical decision-makers with numbers needed to treat or harm, decisions may be better informed and easier to understand, than if proportions alone are used.
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Systematic review and meta-analysis procedures make use of explicit methods to methodically search and critically appraise and synthesize the medical care research literature. The methods involve refining a clinical question, designing a search procedure to find eligible studies, and determining the validity of the eligible studies. Independent data extraction by two or more reviewers is preferred. ⋯ To evaluate a systematic review, first determine whether it addresses a question that is relevant to the patients, treatments, and outcomes that are usual in your clinical practice. Then assess the validity of the systematic review, which is reflected by quality of the individual studies, the rigor with which the systematic methods were applied, and the extent of heterogeneity. If the results of the systematic review are valid, then is the effect important enough to make a difference in your clinical practice? Applying the results to an individual patient involves the absolute treatment effect or the number needed to treat, and an awareness of the patient's specific level of risk and personal preferences.