Topic summary

Second pass at: Trial registration and comparing the protocol with the paper

Evidence › Trials estimand discontinuation & dropout randomised trial open label

This is a generated summary. It shows the 5 most-liked posts from a topic of 35, in their original order, with the accepted answer included where one exists. It is a reading aid and it will miss nuance — the full topic is the record.

h.kjeldsenTL1Member31 May 2025#6

mira.patel, post #1: Posting this under the heading it deserves: Second pass at: Trial registration and comparing the protocol with the paper Everything below is what sits behind that. Two things I would like separated before anyone answers on Trial registration, because they get bundled and then argued about as one thing. The first is descriptive: what has… Go to post

The figure that circulates in coverage is almost always whichever estimand gives the larger effect. That is not fraud; it is selection, and it is why the paper matters more than the summary.

30 likes in reply to #1 14mo

sterile_fileTL3Regular5 Jun 2025#15

f.petrov, post #12: Post #10 is the version of this I will quote in future. One addition. A comparator at less than its maximum licensed dose changes what a head-to-head result means. It does not invalidate the trial; it narrows the claim the trial supports. The interesting part of this is the exception, and I do not understand the exception. Go to post

Post #14 put the caveat in the right place and I want to underline it.

Multiplicity and multiple comparisons: if a trial tests many hypotheses, the chance of a false positive on at least one by random chance increases. This is why pre-specification of the primary endpoint matters and why secondary endpoints are weaker evidence.

The evidence for this is thinner than the way I have phrased it suggests.

29 likes in reply to #12 14mo

NorringtonTL3Regular9 Jun 2025#22

Effect sizes in a trial population reflect adherence achieved under trial conditions, which is generally better than adherence outside them.

30 likes 14mo

z.nakamuraTL212 Jun 2025#29

Picking up post #26: that is the part I would want checked first.

Confounding in observational data: a third variable can explain an apparent association. In a randomised trial, randomisation balances unknown confounders. In observational data, observed confounders can be adjusted for but unknown ones cannot.

I would be interested in a counterexample if anyone has one.

29 likes 13mo

f.novakTL214 Jun 2025 · edited#33

a.stephanopoulos, post #13: Nothing to add, except that this is the answer I would give if asked. Go to post

Trial duration determines what can be observed. A weight-change trajectory at 40 weeks and at 72 weeks are different observations and both get quoted as the result.

25 likes in reply to #13 13mo

Read the full topic (35 posts)

Promoted into the documentation commons. The content of this topic is maintained at Cagrilintide plus semaglutide phase 2 — trial digest, with named maintainers and a review date. The promotion was discussed in doc review. Corrections are best raised against the document, which is the version that gets kept current.

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