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Education And Debate

Commentary: Placebo run ins have some value

BMJ 1997; 314 doi: (Published 19 April 1997) Cite this as: BMJ 1997;314:1193
  1. Lawrence E Ramsay, professor
  1. a Section of Clinical Pharmacology and Therapeutics, Department of Medicine and Pharmacology, Royal Hallamshire Hospital, Sheffield S10 2JF


    Professor Senn is right to question placebo run ins, which have tended to become a ritual in clinical trial protocols. I agree with many of his points, but not all of them, and suggest that placebo run ins should not be abandoned entirely.


    Senn contends that the statistical or scientific case for placebo run ins is weak. I agree that they should not be used generally to weed out non-compliers, responders to placebo, or patients with above average variability. Their use in this way limits the extent to which the study results can be generalised to ordinary practice. I agree entirely that active treatments should not be compared back to baseline values. If the true efficacy of an active treatment is to …

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