Each week, Weight & Measure highlights studies worth your attention, explains their findings, and puts their limits into plain language.
OMMs can support ongoing care after metabolic & bariatric surgery
A systematic review published October 25 examined how GLP-1–based obesity management medications (OMMs) are being used before and after metabolic & bariatric surgery. Researchers reviewed 27 studies, separating the evidence by when treatment began: before surgery, early afterward, or following an insufficient clinical response or weight recurrence. The strongest evidence supported medication use after an insufficient response or weight recurrence. Across four randomized trials, participants receiving medication lost approximately 10.3 percentage points more body weight than those receiving placebo or usual care. These findings support an important conversation about long-term treatment: surgery and medications can be complementary parts of obesity care, and needing additional treatment does not mean a person has failed.
There are important limitations. The randomized trial results varied substantially, so the pooled estimate should not be interpreted as an expected outcome for an individual patient. The review also does not establish one preferred medication or an optimal time to begin treatment. Evidence for routine early postoperative use remains less established than evidence for treating an insufficient response or weight recurrence. Treatment decisions still require attention to nutritional status, tolerability, medical history, and individual goals.
Worth reading: Peer-reviewed systematic review — English abstract ↗ · Related Weight & Measure guide →
Retatrutide outperformed semaglutide 2 mg in a head-to-head diabetes trial
Results announced October 28 offer a new look at how investigational retatrutide compares with an established medication. In TRANSCEND-T2D-2, an 80-week randomized trial involving 1,298 adults with type 2 diabetes, Eli Lilly reported average weight reductions of 19.5% with retatrutide 9 mg and 20.9% with retatrutide 12 mg, compared with 9.4% with semaglutide 2 mg, marketed as Ozempic. Both retatrutide doses also produced greater average A1C reductions: 2.2 percentage points compared with 1.8 percentage points. Direct comparisons are valuable because they can help patients and practitioners understand differences between treatments without relying on results from separate trials involving different populations.
These are preliminary company-reported findings, not a complete peer-reviewed publication. The trial was open label, and the reported efficacy estimates assume participants remained on treatment without starting additional glucose-lowering medication. More participants stopped retatrutide because of adverse events than stopped semaglutide. The comparison was specifically with Ozempic 2 mg; it does not establish superiority over every semaglutide regimen or over tirzepatide. Retatrutide remains investigational, and the full publication will be important for evaluating the balance of benefits, tolerability, and treatment persistence.
Worth reading: Original company announcement and trial results ↗ · Related Weight & Measure guide →
Comparing surgery and medications requires understanding who received each treatment
A study published October 27 in JAMA Network Open examined Medicare claims for 173,344 beneficiaries with documented obesity who underwent metabolic & bariatric surgery or began GLP-1 therapy. Among participants with a BMI code, median coded BMI was 47.5 in the surgery group and 39.5 in the medication group. BMI documentation was also more complete among people undergoing surgery: 99.4% compared with 83.7% among those initiating GLP-1 therapy. These differences matter because observational studies often use insurance claims to compare treatments. If the groups begin with different levels of obesity severity, a comparison that does not adequately account for those differences may give a misleading impression of treatment effectiveness.
The study evaluated documentation and coding, not which treatment produced better health outcomes. Researchers did not have measured height and weight, and the differences could reflect both underlying severity and how thoroughly each group was evaluated. The data covered 2017–2023, when Medicare prescribing patterns differed from today’s obesity treatment landscape. For patients and advocates, the practical takeaway is to look beyond a headline declaring one treatment better and ask whether the study compared sufficiently similar people.
Worth reading: Original peer-reviewed study ↗ · Related Weight & Measure guide →
What we're watching
This week’s findings highlight both the expanding possibilities of obesity treatment and the importance of interpreting evidence carefully. The postoperative review supports studying medications and surgery as parts of continuing care. The retatrutide announcement offers a promising direct comparison, while leaving important questions for the full publication. The Medicare study reminds us that treatment comparisons depend on understanding who received each option in the first place. We will be watching for stronger evidence on medication timing after surgery and the complete retatrutide results, including outcomes that reflect treatment discontinuation. More Science. Less Stigma.
Weight & Measure translates obesity science for the people living it. Educational information only, not personal medical advice.
More science. Less stigma.