Controlled clinical trials
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Control Clin Trials · Dec 1989
Large trials with simple protocols: indications and contraindications.
The design of a clinical trial derives from its objective, which in its turn is dictated by the needs of clinical practice. Therefore, a common condition, a simple treatment, and a simple outcome measure are opportunities rather than design options. ⋯ If the treatment influences an intermediary outcome, which is assumed to have a causal role in the disease process that the treatment eventually seeks to influence, the effect on the intermediary outcome is of great importance--for clinical practice is very much centered around this outcome and the effects on intermediary outcomes may serve as an aid in explaining why there is an effect or why not. In conclusion, there are some research questions that may warrant large and simple trials, but many clinically very relevant research questions require a more complex trial design.