Stomach Bacterium May Not Drive Repeat Ulcer Bleeds in Patients on Blood Thinners

For decades, one of the most stubborn questions in gastroenterology has been how best to protect patients who must take blood-thinning medications yet have already survived a dangerous bleeding ulcer. A new real-world study from Spain now suggests that, in modern clinical practice, one long-standing villain may matter far less than expected in this high-risk group: the stomach bacterium Helicobacter pylori. The research, published in BMC Medicine by a team led by Samuel J. Martínez-Domínguez and Ángel Lanas of the Hospital Clínico Universitario Lozano Blesa in Zaragoza, found that among patients taking antithrombotic drugs, H. pylori status was not significantly associated with a recurrence of peptic ulcer bleeding, a finding that could reshape how clinicians think about prevention in this vulnerable population.

Peptic ulcer bleeding, often abbreviated PUB, is one of the most feared complications in gastroenterology. It occurs when an open sore in the lining of the stomach or the first part of the small intestine erodes into a blood vessel, producing external digestive hemorrhage or a drop in hemoglobin greater than two grams per deciliter. Despite major advances in endoscopic therapy and acid suppression over the past two decades, patients who experience one such bleed remain at elevated risk of another. For those also taking antithrombotic medications—drugs such as antiplatelet agents and anticoagulants that are essential for preventing heart attacks and strokes—the calculus becomes even more delicate, because both the ulcer and the cardiovascular system compete for clinical attention.

The conventional wisdom, embedded in multiple international guidelines, holds that eradicating H. pylori, a spiral-shaped bacterium that colonizes the gastric mucosa and is a principal cause of peptic ulcer disease, is a cornerstone of preventing recurrent bleeding. Yet much of the evidence underpinning that recommendation predates the era of widespread, long-term proton pump inhibitor use, the powerful acid-suppressing drugs that have become near-universal prescriptions after a bleeding event. The Spanish team set out to test whether the bacterium still drives recurrence in a contemporary, real-world population in which acid suppression is the norm rather than the exception.

To answer the question, the investigators conducted a retrospective, multicenter cohort study of consecutive patients who suffered a first episode of peptic ulcer bleeding between 2008 and 2023 in real clinical settings across Spain. To be included, patients required endoscopically confirmed gastric or duodenal ulcers or erosions together with evidence of bleeding. Those with non-peptic causes of upper gastrointestinal hemorrhage, peptic ulcers without bleeding, bleeding from the small bowel or colon, missing clinical data, or death during the index hospitalization were excluded. Follow-up continued until the first recurrence of ulcer bleeding, death, loss to follow-up, or the end of the review period, yielding a mean observation time of 6.4 years with a standard deviation of 4.7 years—a remarkably long window for a study of this kind.

The cohort ultimately comprised 1,675 patients. At discharge after their first bleeding episode, 525 of them, or 31 percent, were prescribed antithrombotic therapy, while 1,021 patients, or 61 percent of the entire cohort, received long-term proton pump inhibitor prescriptions. Notably, among the antithrombotic users themselves, 429 patients, representing 82 percent, were given indefinite PPI therapy, underscoring just how thoroughly acid suppression has penetrated routine care for this group. After the initial bleed and any eradication treatment, 94 patients, or 5.6 percent, remained H. pylori-positive, 936 patients, or 56 percent, tested negative, and 645 patients, or 38 percent, were never tested for the bacterium—a sizable untested fraction that itself reflects themessiness of real-world medicine.

The headline finding for the whole cohort was striking. Overall, 7.2 percent of patients experienced a first recurrence of peptic ulcer bleeding during follow-up. But when the researchers stratified by H. pylori status, recurrence climbed to 22 percent among those who remained positive, fell to 7.7 percent among those who were negative, and dropped to just 4.2 percent among the untested. Using Cox regression analysis adjusted for age, sex, use of non-steroidal anti-inflammatory drugs, and long-term PPI prescription, the team calculated that patients who stayed H. pylori-positive had a 3.7-fold higher risk of recurrence compared with H. pylori-negative patients, with a 95 percent confidence interval of 2.3 to 6.1. When the comparison was restricted to patients who remained positive versus those who had been successfully eradicated, the risk was 4.7 times higher, with a confidence interval of 2.6 to 8.7. In other words, in the general population of bleeders, the bacterium remains a potent and measurable driver of recurrent hemorrhage.

The picture changed dramatically, however, when the researchers turned to the 525 patients on antithrombotic drugs. In this subgroup, the overall incidence of first recurrence was only 5.1 percent. Among H. pylori-positive antithrombotic users, recurrence reached 7.1 percent; among H. pylori-negative users, 8 percent; and among the untested, just 2 percent. Counterintuitively, the positive patients did not fare worse than the negative ones, and after statistical adjustment the team found no significant risk differences across H. pylori status groups. The wide confidence intervals that accompany such subgroup analyses temper any strong claims, but the signal is clear: within this heavily PPI-protected population, H. pylori status no longer predicted who would bleed again.

What might explain this apparent paradox? One plausible mechanism centers on gastric acidity itself. H. pylori promotes ulcer formation and recurrence partly through inflammation and disruption of the mucosal barrier, but acid secretion remains a critical cofactor in the cascade that turns a colonized stomach into a bleeding ulcer. Proton pump inhibitors suppress acid output profoundly and durably, and with 82 percent of antithrombotic users in this cohort taking them indefinitely, the pharmacological floor beneath the mucosa may be high enough that eradicating the bacterium adds little additional protection. In patients without such acid suppression, or in whom PPI therapy is intermittent, the bacterium retains its full pathogenic force—precisely the pattern the whole-cohort analysis revealed. The finding also echoes a broader shift in ulcer epidemiology: as H. pylori prevalence falls and non-steroidal anti-inflammatory drug and antithrombotic use rises, drug-induced mucosal injury has overtaken infection as the dominant cause of bleeding ulcers in many settings.

The authors are careful to frame their work as preliminary, and several limitations deserve attention. The retrospective design means the researchers depended on records and testing practices that varied across centers and years, and the 38 percent of patients never tested for H. pylori introduce the possibility of selection effects—clinicians may have been less likely to test patients they judged to be at low risk. The antithrombotic subgroup, though sizable at 525 patients, yielded relatively few recurrence events, which limits statistical power and widens uncertainty around the null finding. Confounding by indication is also possible, since patients receiving antithrombotics differ systematically from those who do not. The study’s ethics approval came from the ethics committee of Aragón under code EPA22/065, with the informed consent requirement waived owing to the observational design, and the statistical analysis was supported by the Group of Translational Research in Digestive Diseases of the Aragón Health Research Institute, the CIBERehd network, and the FORTALECE program of the Spanish Ministry of Science and Innovation.

Even with those caveats, the implications are hard to ignore. Millions of people worldwide take antithrombotic drugs for cardiovascular protection, and a meaningful share of them carry H. pylori or have uncertain infection status. If prolonged acid suppression largely neutralizes the bacterium’s contribution to recurrent bleeding in these patients, clinicians may be able to prioritize adherence to PPI therapy, careful antithrombotic dosing, and avoidance of non-steroidal anti-inflammatory drugs over exhaustive pursuit of eradication in every case. At the same time, the stark 3.7-fold elevation in recurrence risk among H. pylori-positive patients in the broader cohort is a vivid reminder that eradication remains essential for most survivors of ulcer bleeding. The study does not overturn the eradication paradigm; it carves out a well-defined exception and, in doing so, maps the boundary conditions of one of gastroenterology’s most durable beliefs. Larger prospective studies, ideally with systematic testing of all patients, will be needed to confirm where that boundary truly lies—but for now, the message from Spain is that in the modern, acid-suppressed, real-world clinic, the bacterium’s grip on bleeding risk may be loosening, at least for those whose hearts and vessels demand blood thinners.

Subject of Research: Helicobacter pylori status and recurrence of peptic ulcer bleeding in antithrombotic users

Article Title: No significant association between H. pylori status and peptic ulcer bleeding recurrence among antithrombotic users: a preliminary study in a real-world population with high PPI use

Article References: Martínez-Domínguez, S. J., Ceamanos-Ibarra, E., Gallego-Llera, B., Jiménez-Benedí, M., Bujanda, L., Jardón-Piérola, O., Izaguirre-Arostegi, A., Cuarán, C., Pascual, A., Almenara, L., & Lanas, Á. (2026). No significant association between H. pylori status and peptic ulcer bleeding recurrence among antithrombotic users: a preliminary study in a real-world population with high PPI use. BMC Medicine. https://doi.org/10.1186/s12916-026-05275-z

Image Credits: AI Generated

DOI: 10.1186/s12916-026-05275-z

Keywords: Helicobacter pylori, peptic ulcer bleeding, antithrombotics, proton pump inhibitors, gastrointestinal bleeding, ulcer recurrence, Cox regression, retrospective cohort study, NSAIDs, eradication, BMC Medicine, gastroenterology