Journal club: SURMOUNT-4 and continuation versus withdrawal — setting out what I have, and where I think it stops being reliable.
Trying to establish the boundary conditions on SURMOUNT-4 and continuation versus withdrawal. The general claim is fine; I want to know where it stops holding, because that is where I am operating.
Three edge cases below, in increasing order of how far outside the usual range they sit.
I had written a reply contradicting the opening post and deleted it. Here is what survived.
The failure mode on SURMOUNT-4 and continuation versus withdrawal is boring rather than dramatic. It is almost always the step everyone assumes was done correctly because it is too simple to get wrong.
Confirming post #3 from a second method, which matters more than confirming it from a second person.
The figures usually contain the finding and the text usually contains the interpretation. Separating them for the first twenty minutes is a discipline worth keeping.
Sessions on negative or null results are consistently the most instructive and the hardest to get anyone to attend.
I would rather post the uncertainty than round it away.
Summarising the SURMOUNT-4 and continuation versus withdrawal thread so far, since it is long and the answer is buried: the first reply has the method, the fourth has the correction to it, and the rest is people agreeing at length.
Post #7 is right about the mechanism and I think understates the practical bit.
One more thing on SURMOUNT-4 and continuation versus withdrawal that took me far too long to see: the two figures people quote are not measuring the same quantity. Once you notice that, the apparent contradiction disappears.
Worth separating two things that post #7 runs together.
The most common failure mode is spending fifty minutes on the effect size and ten on the population. Reversing that ratio would improve most sessions.
Appreciated. The plain phrasing does more work here than a longer post would.
Post #8 is the version of this I will quote in future. One addition.
Adding the boring version of SURMOUNT-4 and continuation versus withdrawal, because the interesting version keeps getting posted and the boring one is usually right.
Check the ordinary explanations, in order, and stop when one of them accounts for what you are seeing. Most of the time the second one does.
Where I part company with post #11, and it is a narrow parting.
The confident answers on SURMOUNT-4 and continuation versus withdrawal and the well-sourced answers are not the same answers, which is the most useful thing I have learned reading this category.
The baseline characteristics table is the single most useful page for the questions that get asked here, because it tells you who the result applies to.
It reads as pedantry until the day it does not.
Confirming post #13 from a second method, which matters more than confirming it from a second person.
For anyone finding this later: the short answer on SURMOUNT-4 and continuation versus withdrawal is that it depends on one thing, and the rest of the thread is people identifying which thing.
Reading order that works for these sessions: registry entry, methods, baseline table, primary result, then abstract last. Reading the abstract first anchors everything that follows.
It is worth checking rather than assuming, which costs nothing.
Acknowledging rather than arguing. The reasoning holds as far as I can follow it.
Sessions on negative or null results are consistently the most instructive and the hardest to get anyone to attend.
It is a small point and it changes the answer, which is an awkward combination.
Source for the SURMOUNT-4 and continuation versus withdrawal figure, since it was asked for. It is in the discussion rather than the abstract, which is why the version circulating is stronger than the paper is.
Reading the surrounding paragraph is worth the two minutes. The authors are more careful than their summarisers.
SURMOUNT-1 (N Engl J Med 2022): Tirzepatide obesity trial. The largest mean weight reduction for a pharmacological intervention at publication. Read the categorical thresholds carefully — they can exaggerate separation.
It is worth stating the boring hypothesis before the interesting one.
I had written a reply contradicting post #19 and deleted it. Here is what survived.
The baseline characteristics table is the single most useful page for the questions that get asked here, because it tells you who the result applies to.
Reporting the observation and leaving the explanation open deliberately.
Counterpoint on SURMOUNT-4 and continuation versus withdrawal, offered without confidence: the same observation is consistent with a much duller explanation, and nobody has ruled the dull one out.
The most useful reply I ever got about SURMOUNT-4 and continuation versus withdrawal was a request to state my units. It sounds like pedantry and it has saved me twice.
I read the earlier replies on SURMOUNT-4 and continuation versus withdrawal twice before writing this, because I had assumed the opposite and wanted to be sure I was disagreeing with what was said rather than what I expected.
Fine by me. I had wanted a stronger conclusion and there is not one available.
Worth separating two things that post #23 runs together.
Checked the SURMOUNT-4 and continuation versus withdrawal claim against the primary source this morning. It survives, with a narrower scope than the version quoted here. Posting the narrower scope.
This follows post #27 rather than contradicting it.
The most common failure mode is spending fifty minutes on the effect size and ten on the population. Reversing that ratio would improve most sessions.
I would treat the number as indicative rather than as a measurement.
I would call the community position on SURMOUNT-4 and continuation versus withdrawal likely rather than established, and I would be comfortable defending that hedge.