GLP-1 medicines before an endoscopy: aspiration and stopped procedures

Why this study matters

An upper gastrointestinal endoscopy is a procedure where a thin camera is passed down the throat to look at the oesophagus, stomach and the start of the small bowel. People are usually sedated. If food is still in the stomach, it can come back up and enter the lungs. This is called pulmonary aspiration and can cause serious pneumonia. GLP-1 medicines slow stomach emptying, so there has been concern that people taking them could have food in the stomach even after fasting. This study is one of the largest to test that concern with real procedure data.

Who was in the study

The study included 43365 adults aged 18 and over with type 2 diabetes who had an upper gastrointestinal endoscopy. Everyone had used either a GLP-1 receptor agonist or an SGLT2 inhibitor in the 30 days before the procedure. SGLT2 inhibitors are a different class of diabetes medicine that does not slow the stomach. The data came from two de-identified US commercial health care databases.

After statistical weighting, there were 24817 GLP-1 users (average age 59.9 years, 63.6% female) and 18537 SGLT2 inhibitor users (average age 59.8 years, 63.7% female). Outcomes were measured on the day of the procedure and the day after.

What the researchers did

This was a cohort study, which compares groups of people who were prescribed different treatments rather than assigning them by chance. People on SGLT2 inhibitors were the comparison group because they had diabetes at a similar stage but took a medicine with no known effect on stomach emptying.

The researchers used a method called propensity score fine stratification weighting. This balances the two groups on many recorded characteristics so that they look as alike as possible. Results are reported as risk ratios. A risk ratio compares how often an event happened in one group with how often it happened in the other. A value of 1 means no difference.

The main outcome was pulmonary aspiration, identified from diagnostic codes. The secondary outcome was discontinuation of the endoscopy, meaning the procedure was started but stopped before it was complete.

What they found

Pulmonary aspiration was rare in both groups. The weighted risk was 4.15 per 1000 people among GLP-1 users and 4.26 per 1000 among SGLT2 inhibitor users. The pooled risk ratio was 0.98, with a 95% confidence interval of 0.73 to 1.31 (R32-C127). A confidence interval is the range in which the true value is likely to sit. Because it includes 1, there was no clear difference in aspiration between the groups.

Discontinuation of the endoscopy was more common with GLP-1 medicines: 9.79 per 1000 compared with 4.91 per 1000. The risk ratio was 1.99 (95% CI 1.56 to 2.53). The whole range is above 1, so this difference was statistically clear.

The authors suggest that the higher rate of stopped procedures may be because food was more likely to remain in the stomach in GLP-1 users, although the records did not give the reason for each cancellation.

Side effects and people who stopped

This study measured aspiration and stopped procedures. It does not report other side effects of the medicines. Note that "discontinuation" here means the endoscopy was stopped, not that people stopped taking their medicine.

What this study does not tell you

• This is an observational study in people with type 2 diabetes. It does not directly describe people using GLP-1 medicines for weight management without diabetes.
• Aspiration was identified from diagnostic codes, which may miss mild cases or record some incorrectly.
• The records do not say why each endoscopy was stopped.
• The study does not tell any individual whether to pause a medicine before a procedure. The authors note that randomized trials are lacking and that their findings could inform future guidance.
• The comparison was with SGLT2 inhibitors, not with no medicine.
• The summary we reviewed does not state who funded the study.

What it means in Canada

For Canadian readers, this study offers some reassurance that aspiration during endoscopy was not more common with GLP-1 medicines in a large group of people with diabetes. At the same time, procedures were stopped more often (risk ratio 1.99), which can mean a wasted visit and a repeat appointment. Decisions about medicines before a procedure are made by the procedure team together with the prescriber. See the page on multisociety guidance for GLP-1 medicines before surgery. For how these medicines are used in Canada, see semaglutide in Canada and tirzepatide in Canada.

Related reading

Other studies in this library that bear on the same question.

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