Diabetes: lowering the risk of blood clots - Diabetic H...

Diabetes: lowering the risk of blood clots

Diabetes: lowering the risk of blood clots
Thursday 31 July 2008
guardian.co.uk

If you have diabetes, you may be more likely to get blood clots blocking your blood vessels. This can cause a heart attack or a stroke. If you take medicine to thin your blood, your blood clots less easily. So you may be less likely to have a heart attack or a stroke.

Two blood thinning drugs are mainly used for preventing heart attacks and strokes. They are aspirin and clopidogrel.

In the UK, guidelines for doctors recommend that people with type 2 diabetes with a high risk of heart and circulation problems take aspirin, once their blood pressure is under control.[1]

If you can't take aspirin, your doctor may prescribe clopidogrel (brand name Plavix).

We've looked carefully at the research and divided the treatments into categories, according to how well they work
Treatments that work but whose harm may outweigh benefits

Aspirin
Doctors think that aspirin is likely to cut the risk of having a heart attack or a stroke. But there is a risk of bleeding problems if you take aspirin.

One big review of the research and two other studies have looked at taking aspirin if you have diabetes.[2] [3] [4]

The results were not clear cut. But we do know that:

* In a study of 500 people with diabetes, who had no signs of heart disease, aspirin cut the risk of getting a heart attack or a stroke[3]
* In a group of almost 5,000 people with or without diabetes, aspirin cut the risk of a heart attack or a stroke by a quarter[2]
* If you just look at the people with diabetes in the group, aspirin had less of an effect. But it still cut the risk to some extent.[2]

The main drawback with aspirin is that it can cause bleeding problems, for example bleeding from the back passage (rectum) or bleeding into the brain. Bleeding into the brain is a kind of stroke and can cause brain damage.

To try to avoid this, doctors use a very low dose of aspirin to help prevent heart attacks and strokes. You only need about 75 milligrams (mg for short) to keep your blood thin. This is lower than the dose usually used for pain or arthritis. Most people take between 75 mg and 162 mg daily for blood thinning.

Higher doses don't work any better and they cause more bleeding problems.[2]

You can't take aspirin if you are:[5]

* Allergic to aspirin
* Have certain kinds of bleeding problems
* Are taking more powerful blood thinners (such as warfarin, brand name Coumadin)
* Have recently bled from your intestinal tract
* Have some kinds of liver problems.

Treatments that are likely to work

Clopidogrel
Your doctor may suggest that you take clopidogrel (brand name Plavix) if you can't take aspirin.

There hasn't been any good research that compares clopidogrel with having no treatment.

One large study found that clopidogrel worked about as well as aspirin but caused less bleeding.[6] The study looked at about 4,000 people who had diabetes and who had had a recent stroke, heart attack, or poor circulation in their legs. After a month, between 8 in 10 and 9 in 10 people taking either drug hadn't had a heart attack or a stroke.

Clopidogrel can cause bleeding problems, for example, bleeding from the back passage (rectum) or bleeding in the brain (a kind of stroke). Fewer people who took clopidogrel had problems with bleeding that caused them to be admitted to hospital. About 2 in 100 people who took clopidogrel were admitted, while about 3 in 100 people who took aspirin were admitted.
References

National Institute for Clinical Excellence. Clinical guideline management of type 2 diabetes - management of blood pressure and blood lipids. October 2002. Clinical guideline H. Available at http://www.nice.org.uk/guidance/CGH (accessed on 28 July 2008).

Antithrombotic Trialists' Collaboration. Collaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients. BMJ. 2002; 324: 71-86.

Steering Committee of the Physicians' Health Study Research Group. Final report on the aspirin component of the ongoing Physicians' Health Study. New England Journal of Medicine. 1989; 321: 129-135.

Sacco M, Pellegrini F, Roncaglioni MC, et al. Primary prevention of cardiovascular events with low dose aspirin and vitamin E in type 2 diabetic patients: results of the primary prevention project (PPP) trial. Diabetes Care. 2003; 26: 3264-3272.

American Diabetes Association. Standards of medical care in diabetes. Diabetes Care. 2006; 29 (supplement 1): S4-S42. Also available at http://care.diabetesjournals.org/cgi/content/full/29/suppl_1/s4#/T5 (accessed on 24 July 2008).

Bhatt DL, Marso SP, Hirsch AT, et al. Amplified benefit of clopidogrel versus aspirin in patients with diabetes mellitus. American Journal of Cardiology. 2002; 90: 625-628.