High prevalence of aspirin resistance in elderly patients with cardiovascular disease and metabolic syndrome

Background Metabolic syndrome is known to be a prothrombotic state.We undertook this study to examine a hypothesis that aspirin resistance may be associated with metabolic syndrome,and to assess other potential determinants of aspirin resistance in patients with cardiovascular disease(CVD).Methods A total of 469 elderly patients with CVD were recruited.One hundred and seventy-two patients with metabolic syndrome and 297 without metabolic syndrome(control group) received daily aspirin therapy(≥ 75 mg) over one month.Platelet aggregation was measured by light transmission aggregometry(LTA).Aspirin resistance was defined as ≥ 20%arachidonic acid(AA)- and ≥70%adenosine diphosphate(ADP)-induced aggregation according to LTA.Aspirin semi-responders were defined as meeting one(but not both) of these criteria.Results By LTA,38 of 469(8.1%) patients were aspirin resistant.The prevalence of aspirin resistance was higher in the metabolic syndrome group compared with the control group[11.6%vs.6.6%,odds ratio(OR)=2.039;95%confidence interval(CI):1.047-3.973].In the multivariate logistic regression analysis,metabolic syndrome(OR=4.951,95%CI:1.440-17.019,P=0.011) was a significant risk factor for aspirin resistance.Conclusions A significant number of patients with CVD and metabolic syndrome are resistant to aspirin therapy.This might further increase the risk of cardiovascular morbidity and mortality in these patients.