Patients who kept taking their GLP-1 drug right up to an endoscopy were almost five times as likely to still have food in the stomach when the scope went in. The rate was 4.7 percent, against 1 percent in matched patients with diabetes who were not on the drug. None of them aspirated. None had to be put under general anesthesia.
That is the finding of a retrospective case-control study ↗ published June 25 in the Journal of Clinical Gastroenterology, and it lands on a question that has unsettled the field since 2023.
Why anyone worried
GLP-1 receptor agonists, the class ↗ that includes semaglutide (Ozempic and Wegovy ↗) and tirzepatide (Mounjaro and Zepbound ↗), slow how fast the stomach empties. That delayed emptying is part of how they blunt appetite. It is also why, when a patient is sedated for an upper endoscopy, there is a worry that leftover stomach contents could come back up and be breathed into the lungs, a complication called aspiration that can cause a dangerous pneumonia.
Anesthesia and gastroenterology societies reacted by advising clinicians to hold GLP-1 drugs before procedures, often for a week. The trouble was that the evidence underneath the advice was thin, and it could not separate the drug from the disease. People on GLP-1 drugs usually have diabetes or obesity, and diabetes by itself slows the stomach (a condition called gastroparesis). So when a study found more retained food in GLP-1 users, no one could say whether the drug or the underlying diabetes was the cause.
What the study did differently
The new study matched its groups to strip out that confusion. It compared patients on GLP-1 drugs against patients who also had diabetes but were not on a GLP-1 drug, matched so the two groups shared the same age, sex, body-mass index, and blood-sugar control (A1c). The GLP-1 patients never paused their medication. The analysis covered 417 upper endoscopies and 637 colonoscopies done between January 2018 and June 2023.
With diabetes balanced on both sides, the gap that remained is the drug's own effect. Retained food showed up in 4.7 percent of GLP-1 patients versus 1 percent of the matched controls, a real and statistically significant difference. But inadequate bowel preparation for colonoscopy was identical in the two groups, at 16.5 percent each. Aborted procedures did not differ. And the headline fear, aspiration, did not happen once, in either group.
The part that flips the advice
Here is the result worth stealing. Among the GLP-1 patients, those who came in for an upper endoscopy alone had retained food 9.5 percent of the time. Those who had a colonoscopy at the same visit had it 0 percent of the time. The difference is the prep. A colonoscopy requires a day of clear liquids and a bowel-cleansing purge, and that regimen emptied the stomach the GLP-1 drug was trying to keep full.
So the lever is the preparation, not the prescription. A 24-hour liquid diet before the scope appears to offset the retention the drug causes, which means a patient may not need to interrupt a medication that is managing their weight, blood sugar, or heart risk just to get a routine procedure done safely.
What it does not settle
This is one center, looking backward, with a few hundred procedures per arm. It cannot speak to the rare, severe aspiration event the society guidance was written to prevent, because none occurred here. It does not test the newer drugs head to head, and it cannot tell a patient on a high obesity dose that they are as safe as a patient on a low diabetes dose. What it does is put a number on a risk that had been argued mostly in the abstract, and show that a cheap, already-standard prep step moved that number to zero in the cases studied.
For a class of drugs that keeps generating real-world safety signals ↗, most of them small once you look closely, that is the useful shape: a true effect, a modest size, and a fix that does not require stopping the drug.