Impact of aging on platelet reactivity in diabetic patients receiving dual antiplatelet therapy

Advanced age and diabetes represent summative conditions in the determination of cardiovascular risk, and especially for the management of dual antiplatelet therapy (DAPT), often requiring balancing between bleeding and thrombotic complications. However, few studies have so far evaluated the impact of age on platelet reactivity and suboptimal platelet inhibition (high-on treatment platelet reactivity-HRPR) on DAPT among diabetic patients, that was, therefore the aim of the present study. In diabetic patients treated with DAPT (ASA + clopidogrel or ticagrelor) platelet reactivity was assessed at 30-90 days post-discharge for an acute coronary syndrome or elective PCI. Aggregation was assessed by multiple-electrode aggregometry. HRPR was defined for values above the lower limit of normality (in non-treated patients). Elderly patients were considered ≥ 75 years of age. We included 462 patients, among them 149 (32.2%) were ≥ 75 years. Elderly patients were more often females (p = 0.006), with lower body size (p = 0.04), acute coronary syndrome at presentation and renal failure (p < 0.001), non-smokers (p = 0.002), in therapy with insulin (p = 0.02) and diuretics (p < 0.001) and lower rate of betablockers (p = 0.02). Age directly related with C reactive protein (p = 0.01), creatinine levels and inversely with hemoglobin (p < 0.001) and triglycerides (p = 0.003). No association was found at linear regression analysis for platelet reactivity and age with different activating stimuli, but for ASPI test (r = 0.12; p = 0.03). No significant difference in HAPR was found in elderly patients (2.4 vs. 3.2%, p = 0.76, OR[95% CI] = 0.45[0.1-2.11], p = 0.31). HRPR for ADP antagonists was similarly not affected by age (30.1% vs. 35.7%, p = 0.28, adjusted OR[95% CI] = 0.78[0.47-1.29], p = 0.33). Comparable results were obtained when considering separately the DAPT strategies with clopidogrel or ticagrelor, or when adjusting our results according to propensity score values. Among diabetic patients receiving dual antiplatelet therapy for an acute coronary syndrome or elective percutaneous coronary intervention, age does not affect platelet reactivity or the rate of high-on treatment platelet reactivity. Similar results were obtained for ASA and clopidogrel or ticagrelor.