1. In patients with diabetes mellitus who are on therapy with clopidogrel following percutaneous coronary intervention, high platelet reactivity was more frequent compared to those without diabetes mellitus

2. Patients with diabetes mellitus had an increased risk of major adverse cardiac events compared to those without diabetes mellitus

3. Patients with insulin-dependent diabetes mellitus had an increased incidence of major adverse cardiac events compared to patients with non-insulin-dependent diabetes mellitus 

Evidence Rating Level: 2 (Good) 

Diabetes mellitus and high platelet reactivity (HPR) on clopidogrel are known to be associated with an increased risk of ischemic events following percutaneous coronary intervention (PCI). Studies have demonstrated that in patients with diabetes mellitus, there is a higher prevalence of HPR; however, the association between HPR and thromboembolic events in unknown. In this prospective cohort study, 8582 patients undergoing PCI with drug-eluting stents, loaded with aspirin and clopidogrel were included. Platelet reactivity was assessed after successful PCI using the VerifyNow Aspirin, P2Y12, and IIb/IIa assays. The primary endpoint in this study was definite or probable stent thrombosis. Out of all the patients included in the ADAPT-DES study, 2429 (28.3%) had diabetes mellitus. The results of this study showed that patients with diabetes mellitus had significantly higher mean P2Y12 reaction units than patients without diabetes mellitus, and the frequency of HPR was higher in patients with diabetes mellitus (56.8% vs 37.2%). The increase in HPR in patients with diabetes mellitus was associated with a higher incidence of major adverse cardiac events (aHR 1.44, 95%CI 1.07-1.93). Interestingly, patients with insulin-dependent diabetes mellitus (IDDM) had higher rates of MACE compared with those with non-insulin dependent diabetes mellitus (NIDDM) (aHR 1.02, 95%CI 0.70-1.50; and aHR 2.28, 95%CI 1.39-3.73, respectively). In conclusion, high platelet reactivity was more common amongst patients with diabetes mellitus and was associated with an increased incidence of adverse events. There are several limitations of this study that should be noted. Firstly, individuals with IDDM versus NIDDM may have different therapies such as the use of SGLT2-inhibitors (sodium-glucose cotransporter 2) which can affect cardiovascular health and impact the interpretation of these findings. Additionally, testing for platelet reactivity in this study was only conducted at one time point but this may vary throughout the disease process. Nevertheless, these findings warrant further investigation into variations in ischemic outcomes between NIDDM and IDDM patients, as well as whether diabetics could benefit from increased platelet reactivity testing and different anti-platelet therapy overall. 

Click to read the study in JAHA

Image: PD

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