Please clarify: Do you think that ITT population is for testing efficacy
, safety or both. If it is for efficacy, do we need per-protocol
population, and why?
Dr. Nenad Markovic
Norman Vetter wrote:
> Intention to treat is not the optimum, it is the only way to analyse an RCT
> once the study group has been made up. There may be sub-group analyses later
> but the central question must always be answered according to intention to
> treat allocation
> Norman Vetter
> ----- Original Message -----
> From: "M.J.Campbell" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Friday, August 02, 2002 4:14 PM
> Subject: Intention to treat for cost minimization studies
> > Dear all,
> > Everyone knows that the optimal strategy for analysing an RCT to
> > compare two interventions is by Intention to Treat (ITT). This means
> > that you analyse the study by what treatment the subjects were
> > randomised to, and not what they actually received. Most also know
> > that if one is trying to prove equivalence of treatments rather than a
> > difference, then ITT is not a good idea, since protocol deviations
> > will bias the results towards what you want to prove.
> > Suppose you have a clinical trial with clinical and cost outcomes.
> > Your expectation is that the two treatments will be clinically
> > equivalent, but you want to prove that one is cheaper. Should you
> > analyse by ITT? For the clinical outcomes you have an equivalence
> > trial and for the cost outcomes a difference trial.
> > Have others come across this and what should one do?
> > Mike
> > Professor Mike Campbell
> > Institute of Primary Care and General Practice
> > University of Sheffield
> > Community Sciences Centre
> > Northern General Hospital
> > Sheffield S5 7AU
> > Tel 0114 271 5919
> > Fax 0114 242 2136
> > e-mail [log in to unmask]
> > http://www.shef.ac.uk/michaelcampbell/
> > http://www.shef.ac.uk/medical-statistics/