Aspirin for primary prevention in diabetes ‘should be restricted'
Daily low-dose aspirin treatment does not prevent cardiovascular events or death in people with type 2 diabetes and no previous cardiovascular disease (CVD), and may even increase the risk of coronary heart disease (CHD) in female patients, shows a large cohort study.
Researchers analysed the outcomes of 18,646 men and women with type 2 diabetes and no CVD history, aged between 30 and 80 years, over an average of four years beginning in 2006, using data from the Swedish National Diabetes Registry. In all, 4,608 patients received low-dose (75 mg/day) aspirin treatment while 14,038 patients received no aspirin treatment, giving 69,743 aspirin person-years and 102,754 non-aspirin person-years of follow-up.
Aspirin treatment was not associated with any benefit in terms of cardiovascular outcomes or mortality, after propensity score and multivariable adjustment. Aspirin-treated and non-aspirin-treated groups had equivocal risks of the outcomes non-fatal or fatal CVD, fatal CVD, fatal CHD, non-fatal or fatal stroke, fatal stroke and total mortality.
Patients who received aspirin had a significant 19% increased risk of non-fatal or fatal CHD; further analysis stratifying the group by gender showed this was driven by a significant 41% increased risk in women, while there was no increased risk in men. Women also had a 28% increased risk of fatal or non-fatal CVD.
There was also a borderline significant 41% increase in risk of non-fatal or fatal total haemorrhage with aspirin, but this association became weaker when broken down by gender.
Risks of cerebral or ventricular bleeding did not differ between groups, but aspirin use was associated with a significant 64% increased risk of ventricular ulcer, driven by a 2.3-fold increased in women, while no increased risk was found in men.
Furthermore, the effects of aspirin on these endpoints were similar in patients with high estimated CV risk (five-year risk 15% or higher) and those with low estimated CV risk (five-year risk below 15%).
What this means for GPs.
The results support current guidance from the European Society of Cardiology and the European Association for the Study of Diabetes that do not recommend primary prevention with aspirin in patients with diabetes, but conflict with the NICE type 2 diabetes guidelines, which recommend primary prevention with 75 mg/day aspirin in patients aged 50 years or older if their blood pressure is below 145/90 mm/Hg and in patients younger than 50 who have another significant cardiovascular risk factor.
The authors conclude: ‘The present study shows no association between aspirin use and beneficial effects on risks of CVD or mortality in patients with diabetes and no previous CVD and supports the trend towards a more restrictive use of aspirin in these patients, also underlined by the increased risk of ventricular ulcer associated with aspirin.’