does SELECT actually matter or is it forum lore at this point
The title is the whole question — does SELECT actually matter or is it forum lore at this point — but here is why I am asking.
Went looking for the registered protocol to see whether the endpoint had changed. It had not, which was reassuring and worth checking.
Started keeping the trial identifiers straight in a note file because I kept mixing up two programmes in the same sentence.
Compared myself to a trial mean for about six months before realising the trial arm had dietitian contact every fortnight.
Ask me anything specific. Anything general I will probably get wrong.
best — the order this archive was captured in
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.
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.
Which trial, and which arm?
Absolute or relative risk reduction?
Read a press release and the publication three months apart. The hedging in the second one was substantial.
Is that intention-to-treat or completers?
The press release said that; the publication says something more hedged. Worth reading both.
Correcting myself upthread: I gave the completer figure and labelled it intention-to-treat.
Disagree — that figure is from the diabetes programme and you are quoting it as an obesity endpoint.
Quoted a figure here confidently, got asked whether it was ITT, went and checked, and it was not. Learned something.
SELECT was cardiovascular outcomes, not weight
the appendix is where the interesting tables live
The discontinuation numbers were the most useful thing in the paper for me and they were in a supplementary table.
Spent an evening with the appendix tables and found the subgroup detail that the entire thread had been speculating about.
Cardiovascular outcome trials are powered for events, not for weight, and are typically run in a different population with different inclusion criteria. Reading a weight number out of one is reading a secondary endpoint.
Argued for a week about a result and then read the limitations section, which conceded most of my opponent’s point.
Agreed on comparators. "Superior" means nothing until you know superior to what and at what dose.
That is a relative risk reduction. Quoting it without the absolute numbers overstates the case considerably.
Careful with that mean. The distribution around it was wide enough that it describes very few individual participants.
How long was the randomised phase before any extension?
Yes — the interval is the finding. A point estimate with a wide interval is a hypothesis in a nice font.
Retitled: the original quoted a diabetes endpoint as an obesity result.
Small fix — that was the cardiovascular outcomes trial, so weight was a secondary endpoint and the population was different.
FLOW was kidney outcomes and it is the one nobody quotes
This. Intention-to-treat versus completer analysis routinely moves the headline by several points.
What did the confidence interval look like?
Retitled: the original quoted a diabetes endpoint as an obesity result.
hazard_ratio_hal is right about the programme names. They are different populations with different endpoints.
Do you have the publication or the press release?
That is the 68-week readout, not the 72-week one. Different trial, different duration.
- 1The press release said that; the publication says something more hedged.…9 comments in this branch · started by u/ferran_dahlberg
- 2Yes — the interval is the finding. A point estimate with a wide interval is…9 comments in this branch · started by u/yusuf_ramos