Phil B.FontanarosaMD, Deputy EditorIndividualAuthorStephen J.LurieMD, PhD, Fishbein FellowIndividualAuthor
In Reply: The levels of evidence we proposed
were designed to help inform debates about class effects, not censor them,
and as such we did not define any cutoff between "acceptable" and "unacceptable"
evidence. In doing so, we recognize that reasonable individuals may disagree
about how to interpret the same evidence; however, at least our proposed hierarchy
would provide a framework for the debate.
Although we are aware of the recent innovations in observational study
designs alluded to by Dr Donnan and colleagues, we are concerned about the
progressive distortions in efficacy estimates that occur as we move from RCTs
with concealed allocation to RCTs with open allocation to observational studies.1 As such, we believe that RCTs (and particularly
head-to-head RCTs) remain the evidentiary standard by which interventions
should be evaluated and compared.
McAlister F, Laupacis A, Wells G, Sackett D. Evaluating Clinical Studies of Drug Efficacy—Reply. JAMA. 2000;283(9):1139-1140. doi:10.1001/jama.283.9.1137