Acetylsalicylic acid therapy: influence of metformin use and other variables on urinary 11-dehydrothromboxane B2 levels.

BACKGROUND

The effect of acetylsalicylic acid (ASA) may be measured through the analysis of urinary concentrations of 11-dehydrothromboxane B2 (11-dhTXB2), a metabolite of thromboxane A2, which is a potent platelet aggregant agent. It has been suggested that metformin (an oral antidiabetic drug) could improve oxidative stress and control platelet activation in type 2 diabetic patients, potentially reducing cardiovascular risk. We determined the concentrations of urinary 11-dhTXB2 in type 2 diabetic patients taking ASA and its concentrations with metformin use and several other clinical variables (hypertension, age, gender, smoking, body mass index, insulin and statin use), considering a reduction of at least 75% in the concentrations of this marker as a target, compared to results before ASA intake.

METHODS

Urinary concentrations of 11-dhTXB2 of 81 type 2 diabetic patients were measured before and at 15 days taking 100 mg of aspirin daily.

RESULTS

Most patients who presented a reduction of 11-dhTXB2 above 75% were under metformin use. This reduction was achieved in 51.5% of patients taking this drug, against 20.0% in the patients who were not (p=0.027). The analysis of the other variables did not show a significant difference. The use of metformin appears to play a role in the reduction of 11-dhTXB2 concentrations in type 2 diabetic patients.

CONCLUSION

According to previous reports, hyperglycemia control seems to be a determinant factor for the success of ASA therapy, given the influence of metformin in the reduction of 11-dhTXB2 concentrations.