Antiplatelet Efficacy of 75 mg Aspirin Once a Day versus Twice a Day Dosing in Type 2 Diabetes Mellitus PatientsA Longitudinal Open Label Study

Abstract

Introduction: Patients of Type 2 Diabetes Mellitus (T2DM) characteristically have platelets hyper-reactivity and accelerated turnover rates leading increased adhesion, aggregation and procoagulant activity. Half-life of aspirin is only 20 minutes and it, therefore, irreversibly inactivates limited number of platelets over this short duration, when given as a once-daily dose. Newly generated-active platelets enter circulation, thereafter, and weaken antiplatelet effect of aspirin. Therefore, single daily dose of 75 mg aspirin may be insufficient to provide 24 hours protection against cardiovascular events, in these patients. Aim: To study and compare antiplatelet efficacy of 75 mg aspirin twice a day (75 mg BD) versus 75 mg aspirin once a day (75 mg OD) in patients of T2DM and to study the effect of variation in glycated haemoglobin (HbA1c) levels on antiplatelet efficacy. Materials and Methods: This was a longitudinal, open label, comparative trial conducted at tertiary care hospital for a period of nine months. A total of 129 subjects, diagnosed with T2DM according to American Diabetes Association (ADA) criteria 2018 (N=129) were enrolled in the study, of which nine were lost to follow-up and antiplatelet efficacy of aspirin dosing was examined at baseline and three-monthly intervals thereafter, till nine months, using colorimetric method. Results: Mean age of enrolled patients was 62 years (Interquartile Range (IQR) 57-66). HbA1c levels of both the groups were comparable (p=0.77) at baseline. At the end of nine months, percentage platelet aggregability of the 75 mg B.D. group (29.30±10.39) was significantly lower (p<0.00001) than that of 75 mg OD (38.20±10.36). There was no correlation observed between HbA1c variation and percentage platelet aggregability for entire study population. Conclusion: Present study concludes that, 75 mg OD aspirin as a strategy for secondary cardiovascular disease prevention is advocated, but not adequate in T2DM patients. Splitting a dose of 150 mg/day aspirin as 75 mg twice is more effective, due to increased platelet turnover in diabetic patients.