How likely am I to get reflux on a GLP-1?

This study cannot say. A reporting odds ratio compares how often a term appears among reports, with no count of how many people took the drug, so it produces no incidence or personal risk.

Why did exenatide show the opposite result?

It is unexplained, and it is the most interesting result in the paper. An inverse signal within the same drug class is difficult to attribute to reporting bias, which would tend to lift the whole class together.

Is the Japanese figure the strongest evidence?

It is the largest ratio and the weakest evidence. It rests on 19 reports against 16, which is why its confidence interval runs from 2.45 to 9.27.

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Safety

Do GLP-1 Drugs Cause Acid Reflux? Three Databases Say More Reports

Reporting ratios of 2.83, 2.91 and 4.76 across three countries. Exenatide, in the same class, ran inverse at 0.60.

Glenn TorresSeptember 20268 min read

Reflux is reported more often on a GLP-1 than on its closest drug comparator. Across 260,417 GLP-1 reports in three national databases, the reporting odds ratio was 2.83 in the United States ^[1]. Canada Vigilance gave 2.91 and Japan’s JADER gave 4.76. None of those three numbers is a risk. A reporting ratio counts reports, not patients. Exenatide, in the same class, ran the other way at 0.60. The slowed stomach underneath all of it is set out in the gastroparesis evidence.

What the three databases found

One 2026 study ran the same analysis over the American, Japanese and Canadian adverse event databases ^[1]. The comparator was DPP-4 inhibitors, not the whole database. All three sources produced a signal. FAERS gave 2.83 (95% CI 2.39–3.35). Canada Vigilance gave 2.91 (95% CI 1.97–4.31). Japan’s JADER gave 4.76 (95% CI 2.45–9.27). Semaglutide carried the strongest drug-specific signal in all three. The signal rose with age, reaching 3.01 at 65 and over. Age also tracks the rest of a person’s medication list, which the frailty analysis sets out.

The one drug that ran the other way

Exenatide is an older drug in the same class. In FAERS it returned a reporting odds ratio of 0.60 (95% CI 0.46–0.77). That is fewer reflux reports than the comparator, not more. Disagreement inside one class is hard to explain by notoriety. Attention should lift a famous class together, not push one member below the line.

The objection still holds for the rest of the class. Semaglutide is the most discussed medicine on the market. Attention drives reporting, and the drug with the most attention carries the strongest signal. This design cannot separate those two facts. Consistency across three countries does not fix it, because the same drug is famous in all three.

The mechanism has been measured directly

Reflux would run through delayed gastric emptying. That has a measurement of its own. Gastric ultrasound was performed on 124 patients who had followed standard fasting instructions ^[2]. Retained stomach contents were found in 56% against 19% of the unexposed group. The adjusted prevalence ratio was 2.48 (95% CI 1.23 to 4.97). Stopping the drug earlier did not help: the adjusted odds ratio for interruption length was 0.86 (95% CI 0.65 to 1.14). The procedural consequence is in what to tell the anesthesiologist.

Where the far end of it sits

Gastroparesis is delayed emptying severe enough to carry a diagnosis. A systematic review searched four databases to October 2025 and found twelve case reports covering thirteen patients ^[3]. Onset ran from hours to several months. It usually followed a dose increase or a restart after a gap. Stopping the drug resolved it in every reported patient. Thirteen cases is not a rate, because a case series has no denominator.

What a reader can do with this

Take direction, not magnitude. Reflux belongs on the list of plausible effects of this class. Exenatide means it is not obviously a class effect. Nothing here states how likely it is for any one person. Trial-based figures carry denominators and are the place to look. The escalation pattern behind most stomach complaints is in titration and nausea. The wider safety picture is in the cancer risk evidence.

Frequently asked

Do GLP-1 drugs cause acid reflux?: Reflux is reported disproportionately often on them. Reporting odds ratios were 2.83 in the US database, 2.91 in Canada and 4.76 in Japan, against DPP-4 inhibitors as the comparator. Exenatide, in the same class, ran inverse at 0.60.
How likely am I to get reflux on a GLP-1?: This study cannot say. A reporting odds ratio compares how often a term appears among reports, with no count of how many people took the drug, so it produces no incidence or personal risk.
Why did exenatide show the opposite result?: It is unexplained, and it is the most interesting result in the paper. An inverse signal within the same drug class is difficult to attribute to reporting bias, which would tend to lift the whole class together.
Is the Japanese figure the strongest evidence?: It is the largest ratio and the weakest evidence. It rests on 19 reports against 16, which is why its confidence interval runs from 2.45 to 9.27.

Sources

[1] Choi JG, Gong EJ, Bang CS, Lee JJ (2026). Multi-Database Pharmacovigilance Analysis of Gastroesophageal Reflux Disease Associated with GLP-1 Receptor Agonists: A Cross-National Signal Validation Study Gut and Liver. PMID 42682267
[2] Sen S, et al. (2024). Glucagon-Like Peptide-1 Receptor Agonist Use and Residual Gastric Content Before Anesthesia JAMA Surgery. PMID 38446466
[3] Olubodun T, et al. (2026). Gastroparesis induced by glucagon-like peptide-1 receptor agonists: A systematic review of clinical features, diagnosis, management, and outcomes PLOS ONE. PMID 42594084