SELECT: what the trials say vs what this community says
SELECT: what the trials say vs what this community says — a position I have arrived at slowly and would like tested. Why comparing across trials almost never works, with the specific failure modes. Different populations: an obesity programme and a diabetes programme enrol different people with different baseline…
On means, which this board treats as targets and which are nothing of the sort.
A reported mean body weight change is the centre of a distribution that in these trials is very wide. Substantial numbers of participants did much better, and substantial numbers did considerably worse while remaining on the drug and in the analysis.
Quoting the mean as an expectation therefore misleads in both directions: it makes ordinary results look like failures and it makes exceptional results look normal. If a paper publishes the distribution — and several do, in the appendix — look at that instead. It is far more informative than the number in the abstract.
Discontinuation rates are a tolerability result. A trial with a strong efficacy number and heavy discontinuation is telling you two things and people only quote one.
Which trial, and which arm?
Quoted a figure here confidently, got asked whether it was ITT, went and checked, and it was not. Learned something.
Which trial, and which arm?
Agreed. And the interval, not the point estimate, is what the trial actually established.
discontinuation rate is a result, not a footnote
the appendix is where the interesting tables live