Large (But Simple) Trials: When Are They Justified

Trials, designed to evaluate the therapeutic or prophylactic effect of a treatment on a chronic condition such as heart disease, often require thousands of patients to provide the power required to detect a small but clinically important treatment effect. The complexity and cost of the large scale multicenter trial has made it difficult to obtain the support needed to carry them out. There is a need to find ways to reduce the cost of large scale trials if they are to remain in our armamentarium of evaluation tools, especially in this age of shrinking research budgets. This paper examines the major factors which contribute to the cost of large scale trials and conditions required before it is possible to consider simplified data collection and follow-up procedures. Special emphasis is given to the difficulty scaled down data collection efforts may cause when the safety of the study treatment is in doubt and when the test treatment must be administered over an extended period of time, as in drug trials providing long term therapy for a chronic condition.