walking through what SURMOUNT-4 actually showed about stopping, since it gets misquoted constantly
See SURMOUNT-4 cited a lot in tapering discussions, often slightly wrong, so here's my attempt at describing what the withdrawal arm actually showed rather than the telephone-game version.
SURMOUNT-4 (JAMA, 2024) had participants titrate up on tirzepatide, then randomized a subset to either continue the drug or switch to placebo. The placebo/withdrawal group regained a substantial portion of the weight they'd lost over the following months, while the continued-treatment group kept losing or held steady. It's genuinely one of the clearest published pictures of what happens when the drug stops versus continues.
What it does NOT show: what happens with a slow, deliberate taper (dose reduction over time) rather than an abrupt stop. The trial design was continue-vs-stop, not fast-stop-vs-slow-taper. People extrapolating "SURMOUNT-4 proves slow tapering doesn't help" are reading a claim the trial didn't test.
best — the order this archive was captured in
this is a good-faith and accurate summary, and the "it wasn't a taper-speed comparison" point is the one I see get lost most often. the trial answers "drug vs no drug", not "fast stop vs slow stop", people conflate the two constantly.
exactly why I wrote it, saw three threads this month alone treating it as if it settled the taper-speed question when it never asked that question
the confidence interval on the regain magnitude is also worth remembering exists even if most people never see the actual figure, headline numbers always undersell the spread
and the regain curve over time matters more than a single endpoint number too, where the curve is steepest tells you more than the final value alone
agreed, though I don't have the exact shape of that curve memorized well enough to describe it precisely here, would want to actually pull the supplementary figures before saying more
same pattern with STEP 4, which did something similar with semaglutide, continue vs switch to placebo after a lead-in period, and also showed regain in the switched group. Two separate drugs, same basic message: stopping (abruptly, in both trial designs) predicts regain, that's a well-supported claim. "Therefore tapering slowly is pointless" is the unsupported leap layered on top. edit: originally wrote STEP 1 here, meant STEP 4, wrong number in the trial name, fixed.
always ask what the placebo arm actually did in these trials, in both cases it's not "did nothing ever" it's "abruptly removed after an active period", which is a specific and different thing from a deliberate taper
Flairing Trial Data. This is exactly the kind of careful, hedged citation use this community should model — separating what the trial showed from the popular misreading of it.
worth adding ITT vs per-protocol nuance too, if there was meaningful dropout in either arm the headline regain number can shift depending on which analysis is reported, always worth checking which one is being quoted.
appreciate that this whole post cites correctly and still flags the limits of what's cited, more of this please
would love an actual trial comparing taper speeds directly, feels like an obvious gap in the literature given how much this community discusses it
saving this whole breakdown, been repeating the wrong version of this to myself for months
this is exactly the standard of citation use this whole site should aim for, precise about what's known vs assumed
- 1this is a good-faith and accurate summary, and the "it wasn't a taper-speed…5 comments in this branch · started by u/hazard_ratio_hal