Klinische und Methodische Implikationen der Prärandomisation bei Klinischen Studien

Summary

It is the now a widely accepted position of scientific empiricism that we consider therapy an experiment that almost regularly becomes com- plicated as deviations from an — explicitly or implicitly — prede- termined protocol are unavoidable. In this context informed consent appears to be just an additional complication. Recently, due to legal positions, informed consent has prompted the doctor-patient relationship to bve reconsidered, giving more weight to the patient. Under these conditions Zelen suggested that information should be limited in clinical trials by allowing patients to be randomized prior to their giving consent in order to spare the patient the trouble of decision making and thus to avoid diminishing accrual rates. The patients’s precarious confidence in his or her doctor is said to be backed up by deception (‘telling a little lie’) after the randomized treatment is known to the doctor. Actually, the gain in accrual attributable to prerandomization turns out to be rather small. As only confounded effects of tratments and self-selection can be considered in Zelen’s design, an interpretation of the results may be unsatisfactory if the proportion of non-consenting patients cannot be neglected. What can be learned from the recent controversies about prerandomization is not to exclude these patients from analysis in a conventionally randomized trial as presumably they provide the basis for a better understanding of self-selection.