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Causality: well established
Causality assessment · Causality: well established
Apixaban and Gastrointestinal bleeding: is the FAERS signal real?
A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.
Apixaban ↔ Gastrointestinal bleeding
n=1,649 co-reports · PRR 6.3 · ROR 6.4
Apixaban, a direct factor Xa inhibitor, increases the risk of bleeding — including from the gut — as the expected pharmacodynamic consequence of anticoagulation, though its gastrointestinal bleeding rate is lower than warfarin's in the major randomized trials. The risk is dose-related and is greater with age, kidney impairment, and interacting drugs. The 1,649 co-reports (PRR 6.3) reflect both the real effect and apixaban's very large real-world use.
Regulatory basis: apixaban prescribing information (bleeding warning); ARISTOTLE randomized trial versus warfarin.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Bleeding occurs during anticoagulation and typically stops after withdrawal |
| Strength | met | PRR 6 on a large co-report count |
| Consistency | met | Reproduced in randomized outcome trials and large cohorts |
| Specificity | partial | An anticoagulant-class effect rather than apixaban-specific |
| Biological gradient | partial | Dose-related and worse with age, renal impairment, and interacting drugs |
| Plausibility | met | Factor Xa inhibition impairs haemostasis as the pharmacodynamic extension |
| Coherence | met | Coheres with the bleeding-focused labelling |
| Experiment | met | Randomized evidence (ARISTOTLE) quantifies the risk |
| Analogy | met | Analogous to bleeding with rivaroxaban, dabigatran, and warfarin |
This page's own qualitative read, not an automated/citation-gated assessment.
✗ The results-posting apixaban trial that surfaced (NCT00633893) recorded only a handful of serious bleeding events across arms; the bleeding risk is quantified by the large randomized outcome trial ARISTOTLE and real-world cohorts rather than this extended-treatment AE table.