Non-adherence to aspirin in patients undergoing coronary stenting: Negative impact of comorbid conditions and implications for clinical management

Background. - Premature discontinuation of and reduced adherence to antiplatelet therapy have been identified as major risk factors for stent thrombosis and poor prognosis after acute coronary syndrome. Aim. - We aimed to identify correlates of non-adherence to aspirin among patients who had undergone coronary stenting. Methods. - We prospectively included all patients who had undergone coronary stenting in our institution. Response to aspirin was assessed during the hospital phase with arachidonic acid-induced platelet aggregation (AA-Ag) and only good responders to aspirin (AA-Ag < 30%) were included in the study for longitudinal assessment (n=308). Response to aspirin was reassessed 1 month after hospital discharge and non-responders received a directly observed intake of aspirin to exclude any biological non-response due to bioavailability problems. After excluding patients with such problems, response to aspirin based on platelet function testing was used to estimate non-adherence to aspirin after coronary stenting. A logistic regression model was used to identify predictors of non-adherence. Results. - Non-adherence to aspirin concerned 14% of the study sample (n=43). After adjustment for age, those who reported the highest risk of non-adherence to aspirin were migrants (odds ratio [95% confidence interval], 8.3 [3.5-19.8], followed by patients receiving treatment for diabetes (4.5 [1.9-10.9]). Smokers had a threefold risk of non-adherence (3.1 [1.4-6.9]). Conclusions. - Non-adherence to aspirin is relatively frequent in populations at high risk of cardiovascular events. Appropriate case management and special interventions targeting these groups need to be implemented to avoid fatal events and assure long-term adherence to treatment. (C) 2011 Elsevier Masson SAS. All rights reserved.