Aspirin resistance associated with HbA1c and obesity in diabetic patients.

Introduction: Diabetes is known to be a prothrombotic state. Since serotonin uptake plays a role in both platelet activation and depression, we undertook to examine a hypothesis that aspirin resistance (AR) may be associated with both HbA1c and depressive symptoms and to assess other potential determinants of AR in diabetic patients.
Methods: A whole-blood desktop platelet function analyzer (PFA-100) with an epinephrine agonist was used to assess AR among patients with type 2 diabetes. AR was defined as PFA closure times <192 s. Depression symptoms were assessed with the Physicians Health Questionnaire. Patients being treated for type 2 diabetes (N=48) who took aspirin within the past 24 h constituted the study sample. Associations with AR were assessed with the use of the Mann-Whitney test and Fisher's Exact Test as well as with logistic regression models.
Results: AR was observed in 11 patients (23%) and was not significantly associated with age, sex, or race. AR was significantly associated with HbA1c > or = 8% (P=.002) and obesity (BMI> or = 30 kg/m(2); P=.01) and borderline associated with having > or = 1 depressive symptom (P=.07). Results were similar after multivariable adjustment in logistic regression models. No statistically significant associations of AR with age, sex, race, plasma glucose, blood pressure, cholesterol, or smoking were observed.
Conclusion: These data suggest that AR may be of special concern for diabetic patients with poor glucose control and obesity. Whether the PFA-100 or any other practical measure of AR can be used in clinical practice to identify added cardiovascular disease risk and to inform platelet inhibition therapy needs further study.