Variation in Platelet Reactivity due to Severity of Diabetes in Patients with Acute Coronary Syndrome (ACS)

Abstract

Background: Adverse outcomes in acute coronary syndrome (ACS) patients are associated with high on treatment platelet reactivity (HPR). Diabetes is a known risk factor for HPR, although how severity of diabetes influences HPR has not been described. Our hypothesis is that on treatment platelet reactivity increases with increasing severity of diabetes. Methods: 607 ACS patients on aspirin and clopidogrel undergoing coronary angiography underwent platelet aggregometry measurement. Patients were categorised into non-diabetic (ND) and diabetic. Diabetic patients were subcategorised using the treatment regimen as a measure of diabetes severity: diet controlled (diet); oral hypoglycaemics (oral); and insulin (insulin) treatment.We also collected 30 dayMACE (death, myocardial infarction, heart failure, and stent thrombosis). Results: Diabetic patients had higher measures of platelet reactivity (measured in PRU) than non-diabetics (ND 40.1 PRU, Diet 42.7 PRU, Oral 51.2 PRU, Insulin 55.5 PRU, P= 0.0001) and correspondingly higher rates of HPR (ND32%,Diet 33%,Oral 49%, Insulin56%,P= 0.004).There was a trend towards a higher 30 dayMACE rate in diabetic patients (13%Diabetic vs. 8%ND, P= 0.06) but thiswas not statistically significant. Conclusion: Increasing severity of diabetes was associated with increased levels of on-treatment platelet reactivity, but at 30 days diabetic patients did not demonstrate statistically increased MACE rates. Longer term follow-up is required to examine the significance of the differences in platelet reactivity across the spectrum of diabetes.