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 characteristics. Different endpoints: body weight change, glycaemic control and cardiovascular events are not convertible. Different durations: 68 weeks and 72 weeks are not the same, and the curves have not flattened by either.
Different analysis populations: one paper reports intention-to-treat, another emphasises completers. Different support: some trial designs include structured lifestyle contact that no member of this board receives.
Stack those and the "X beats Y" tables that circulate here are comparing five things at once and attributing the difference to the molecule.
A confidence interval is the range of effects compatible with the data. Two trials with overlapping intervals have not disagreed, whatever their point estimates look like next to each other.
Intention-to-treat analyses everybody randomised regardless of what they did afterwards. Completer analyses only those who finished. The second is systematically more flattering and both are legitimate if labelled.
If somebody has the same thing measured a different way, post it next to mine and we will see whether they agree.
best — the order this archive was captured in
Open-label extensions lose their randomisation. Anybody still enrolled at week 104 is a selected group and the numbers describe that group.
This. Intention-to-treat versus completer analysis routinely moves the headline by several points.
Read a press release and the publication three months apart. The hedging in the second one was substantial.
Compared myself to a trial mean for about six months before realising the trial arm had dietitian contact every fortnight.
Careful with that mean. The distribution around it was wide enough that it describes very few individual participants.
read the endpoint before you read the headline
Not convinced. Cross-trial comparison between two programmes with different populations and designs is not a comparison.
Quoted a figure here confidently, got asked whether it was ITT, went and checked, and it was not. Learned something.
That is the 68-week readout, not the 72-week one. Different trial, different duration.
Added the trial identifier to the title so this thread is findable in two years.
FLOW was kidney outcomes and it is the one nobody quotes
phase 2 finds a dose, phase 3 measures the effect
Added the trial identifier to the title so this thread is findable in two years.
This is the distinction that would end about half the arguments on this board.
the appendix is where the interesting tables live
Started keeping the trial identifiers straight in a note file because I kept mixing up two programmes in the same sentence.
Disagree — that figure is from the diabetes programme and you are quoting it as an obesity endpoint.