Prevalence and Risk Factors for Aspirin Resistance in Elderly Patients With Type 2 Diabetes

Summary Background Aspirin resistance in patients with diabetes is recognized. However, the prevalence and related risk factors for aspirin resistance in elderly patients with Type 2 diabetes have not been reported, which is why we undertook this study. Methods One hundred and forty elderly patients (age, 73.84 ± 8.02 years) with Type 2 diabetes receiving daily aspirin therapy (≥75 mg) over 1 month were recruited. Platelet aggregation was measured by light transmission aggregometry (LTA) and thrombelastography (TEG) platelet mapping assay. The definitions of aspirin resistance were 20% or greater arachidonic acid-induced and 70% or greater adenosine diphosphate-induced aggregation by LTA. Aspirin semiresponders were defined as meeting one (but not both) of these criteria. Aspirin resistance by TEG was defined as 50% or greater aggregation induced by arachidonic acid. Results By LTA, 6 (4.3%) patients with Type 2 diabetes were found to be resistant to aspirin therapy; 44 (31.4%) patients were semiresponders. By TEG, 31 patients (22.1%) were aspirin resistant. Of the 31 patients who were aspirin-resistant by TEG, 3 were aspirin-resistant by LTA. Eight of 44 semiresponders by LTA were aspirin-resistant by TEG. In the multivariate logistic regression analysis, being female (odds ratio: 5.54, 95% confidence interval: 1.17–27.47, p  = 0.036) and homocysteine levels (odds ratio: 1.15, 95% confidence interval: 1.00–1.31, p  = 0.043) were significant risk factors for aspirin resistance by TEG. Conclusion The prevalence of aspirin resistance in elderly patients with Type 2 diabetes was considerably higher in female patients and in patients with higher serum levels of homocysteine.