Discrepancies in Assessment of Adherence to Antiplatelet Treatment after Myocardial Infarction

Abstract

The poor response to clopidogrel is multifactorial and includes, amongst others, low patient adherence to medication. The aim of this study was to assess the reported patient adherence to treatment with clopidogrel and confront it with adherence assessed by drug availability. We evaluated determinants of adherence and its impact on platelet aggregation and clinical outcome. The study population comprised 184 patients treated with primary percutaneous coronary intervention for acute myocardial infarction. Follow-up visits were scheduled at 3, 6 and 9 months after discharge. Patient adherence to clopidogrel was defined according to self-reported drug intake and verified based on data from the National Health Fund regarding the purchase of prescribed drugs. The patients were judged as adherent when the proportion of drug availability exceeded 80%. According to drug availability, 100 (54.3%) patients were adherent and 84 (45.7%) were nonadherent. The analysis identified the following factors as predictors of low adherence (<80%): adenosine diphosphate-induced platelet aggregation (ADP-PA) during hospitalization ≤45 U, male gender and occurrence of ST-elevation myocardial infarction [(STEMI) vs. non-STEMI (NSTEMI)], while three-vessel disease was predictive of high adherence to medication. Compared with drug availability-based assessment, self-reported drug intake was significantly different: 172 (94.5%) patients reported regular and 10 (5.5%) patients reported irregular intake of clopidogrel. Clinical follow-up suggested that the self-reported nonregular clopidogrel intake may discriminate patients with a high risk of cardiovascular events. We demonstrated a huge discrepancy between the two most widely used methods for the evaluation of adherence to clopidogrel in secondary prevention treatment in patients after STEMI and NSTEMI. ADP-PA during hospitalization ≤45 U, male gender and STEMI (vs. NSTEMI) were independent predictors of nonadherence while three-vessel disease was independently predictive of adherence to treatment with clopidogrel in the investigated population.

Relation of the Readiness for Hospital Discharge after Myocardial Infarction Scale to socio-demographic and clinical factors. An observational study

“…These observations are difficult to explain and partly inconsistent with the results of other publications [20]. In previous studies [5,[21][22], women achieved slightly lower results in terms of knowledge regarding coronary artery disease, and the effectiveness of in-hospital education was similar for both sexes [13,[21][22]. Our observations concerning the differences related to the place of residence were similar to the results obtained in previous studies [5,[21][22].…”

“…Effective education should positively influence the patient's behaviour in reducing risk factors, self-control and adherence to prescribed pharmacotherapy [7,[9][10][11]. On the other hand, non-adherence to medical recommendations results in serious health and economic consequences [12][13][14][15]. The Readiness for Hospital Discharge after Myocardial Infarction Scale (RHD MIS) is a validated tool allowing the assessment of patients before leaving the hospital [16].…”

Effectiveness of therapeutic education in patients with myocardial infarction

“…They proved to be effective both with reference to endorsement of the recommendations from the therapeutic team by the patient, as well as with respect to active participation of the patient in the process of preparing the personal therapeutic plan [7,8].…”

Self-reported questionnaires for assessment adherence to treatment in patients with cardiovascular diseases

“…Considering that approximately half of the patients requiring treatment due to chronic disease do not adhere to the therapeutic plan, the assessment of patient adherence to treatment plays a pivotal role in the description and verification of the therapeutic process [43][44][73][74][75]. Thus, the search for available tools for adherence assessment as well as evaluation of their characteristics is necessary [76][77][78].…”