Causes of gastrointestinal bleeding in oral anticoagulant users compared to non-users in a population-based study

Abstract

Background/aims

Causes of gastrointestinal bleeding (GIB) in patients on oral anticoagulants (OACs) are not well established. The aims of the study were to compare the causes of GIB in patients on OACs and those not on OAC therapy.

Methods

A nationwide study of all GIB events in patients on OACs in Iceland from 2014–2019 was conducted. Bleeding events were obtained through ICD-10 codes and review of endoscopy databases, confirmed by review of medical records. For comparison, patients not on OACs from previous Icelandic population-based studies were used.

Results

Among 752 GIB events in 12,005 patients on OACs, 273 (1.9%) had verified upper and 391 (2.7%) had verified lower GIB. For lower GIB, multivariate analysis showed that OAC users were more likely to have colonic polyps (OR 6.6, 95% CI: 2.4 − 17.8, p < .001) or colorectal cancer (OR 3.7, 95% CI: 2.0 − 7.0, p < .001) but less likely to have ischemic colitis (OR 0.11, 95% CI: 0.04 − 0.26, p < .001). For upper GIB, bleeding from mucosal erosions (OR 4.0 95% CI: 2.5 − 7.9, p < .001) and angiodysplasia (OR 3.6, 95%CI: 1.5 − 8.6, p = .003) were more common in OAC users.

Conclusions

A high proportion of GIB caused by colonic polyps and colorectal cancer among OAC patients indicates that OACs treatment may facilitate cancer diagnosis. The low proportion of ischemic colitis among those on OACs suggests that OACs provide a protective effect against ischemic colitis. OACs seem to increase the bleeding from angiodysplasia and mucosal erosive disease.

Keywords:

• Gastrointestinal bleeding
• anticoagulation
• colon cancer
• ischemic colitis

Disclosure statement

No potential conflict of interest was reported by the authors.

Guarantor of the article

Einar S. Bjornsson MD, PhD.

Authors’ contribution

All authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Concept and design: J.P.H. and E.S.B. Acquisition, analysis, or interpretation of data: A.S.A., A.B.I., E.R., D.P., I.E.R., J.P.H. and E.S.B. Drafting of the manuscript: A.S.A., A.B.I., J.P.H. and E.S.B. Critical revision of the manuscript for important intellectual content: all authors. Statistical analysis: A.S.A. and J.P.H. Obtained funding: A.S.A., J.P.H. and E.S.B. Administrative, technical, or material support: all authors. Supervision: E.S.B. and J.P.H. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted. All authors have read and approved the final draft of the manuscript.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author, [ESB]. The data are not publicly available due to [restrictions e.g. their containing information that could compromise the privacy of research participants].

Additional information

Funding

The writing and preparation of this paper were supported and funded in part by the research grant of Eimskipasjodur University of Iceland [nr 96512] and the Scientific grant of Landspitali [nr A-2021-011]. The funders of the study had no role in the design and conduct of the study, the collection, analysis, and interpretation of data, or writing of the report. The corresponding author had full access to all data in the study and the final responsibility for the decision to submit for publication.