For decades, low-dose aspirin was routinely recommended for people with diabetes as a cardiovascular preventive measure. Recent large-scale trials have fundamentally changed this approach. The current evidence suggests that aspirin’s benefits in diabetes are far more limited than previously believed — and its risks more significant. Here is what the latest guidelines actually say.
How Aspirin Works
Aspirin irreversibly inhibits cyclooxygenase-1 (COX-1) and COX-2 enzymes, reducing the production of thromboxane A2 in platelets. This reduces platelet aggregation and clot formation — the mechanism by which aspirin prevents heart attacks and strokes in people with established cardiovascular disease.
The Evidence: ASCEND and ARRIVE Trials
Two landmark trials published in 2018 fundamentally altered the aspirin landscape in diabetes. The ASCEND trial enrolled 15,480 people with diabetes without established cardiovascular disease and randomised them to aspirin 100mg daily or placebo. Aspirin reduced serious vascular events by 12% — but this benefit was almost exactly offset by a 29% increase in major bleeding events (gastrointestinal and intracranial haemorrhage). The net clinical benefit was essentially neutral.
The ARRIVE trial similarly found no benefit of aspirin in moderate-risk patients without established cardiovascular disease, with bleeding complications outweighing any cardiovascular protection.
| Patient Group | Aspirin Recommendation |
|---|---|
| Established CVD (secondary prevention) | Recommended — 75–100mg daily |
| High CV risk without established CVD | Consider — if bleeding risk is low; shared decision-making |
| Low-to-moderate CV risk (primary prevention) | Not recommended — bleeding risk outweighs benefit |
Who Should Take Aspirin?
Aspirin remains clearly indicated for secondary prevention — that is, in people who have already had a heart attack, stroke, or have undergone coronary revascularisation. In this group, the benefits are well-established and the risk-benefit balance is clearly favourable.
For primary prevention (people with diabetes who have not yet had a cardiovascular event), aspirin is no longer routinely recommended. The decision should be individualised based on cardiovascular risk, bleeding risk, age, and patient preference — discussed in a shared decision-making conversation with your doctor.
If you have established cardiovascular disease, continue aspirin as directed. If you are taking aspirin for primary prevention of cardiovascular disease and have not had a heart attack or stroke, discuss with your doctor whether it is still appropriate — the evidence no longer supports routine use in this group. Never stop aspirin without medical advice if you have established CVD.

