open access

Vol 74, No 1 (2016)
Original articles
Published online: 2015-06-18
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Prediction of high risk of non-adherence to antiplatelet treatment

Aldona Kubica, Karolina Obońska, Michał Kasprzak, Beata Sztuba, Eliano Pio Navarese, Marek Koziński, Iwona Świątkiewicz, Magdalena Kieszkowska, Małgorzata Ostrowska, Grzegorz Grześk, Jacek Kubica
DOI: 10.5603/KP.a2015.0117
·
Kardiol Pol 2016;74(1):61-67.

open access

Vol 74, No 1 (2016)
Original articles
Published online: 2015-06-18

Abstract

Background: Dual antiplatelet therapy with acetylsalicylic acid (ASA) and clopidogrel is the standard of care for secondary prevention. Premature discontinuation of clopidogrel is associated with an increased risk of myocardial infarction (MI) or death, and greater health care expenditure.

Aim: To develop an objective method for identification of patients with high risk of non-adherence to clopidogrel after MI.

Methods: A total of 189 patients were enrolled into a prospective, observational, single-centre study with a nine-month follow-up. Patients received a 600-mg loading dose and 75-mg maintenance dose of clopidogrel in combination with ASA doses of 300 mg and 75 mg, respectively. Adenosine diposphate-induced platelet aggregation (ADP-PA) was assessed during baseline hospitalisation and at three, six, and nine months after discharge. Adherence to medication with clopidogrel was defined as the proportion of drug availability based on data from the National Health Fund regarding prescribed drug purchases. Adherence was arbitrarily judged adequate when the proportion exceeded 80%.

Results: According to our hypothesis, ADP-PA in non-adherent patients should be higher at follow-up visits (at least once) as compared with measurement at hospitalisation. Based on the ROC curve analysis, the optimal cut-off point equal to 4 U was defined (p < 0.0001, 95% CI 0.562–0.654; sensitivity: 60.6%, specificity: 57.1%, positive predictive value: 63.3%, negative predictive value: 54.2%). The prevalence of true adherence to medication in groups of high and low probability of adherence defined according to developed criteria amounted 60 (50.8%) and 23 (32.4%) cases, respectively (p = 0.01).

Conclusions: The newly developed method of objective identification of patients with high risk of non-adherence to clopidogrel after MI is easily applicable and cheap, and, despite relatively low sensitivity and specificity, it efficiently differentiates patients with regard to clinical end-points during follow-up.

Abstract

Background: Dual antiplatelet therapy with acetylsalicylic acid (ASA) and clopidogrel is the standard of care for secondary prevention. Premature discontinuation of clopidogrel is associated with an increased risk of myocardial infarction (MI) or death, and greater health care expenditure.

Aim: To develop an objective method for identification of patients with high risk of non-adherence to clopidogrel after MI.

Methods: A total of 189 patients were enrolled into a prospective, observational, single-centre study with a nine-month follow-up. Patients received a 600-mg loading dose and 75-mg maintenance dose of clopidogrel in combination with ASA doses of 300 mg and 75 mg, respectively. Adenosine diposphate-induced platelet aggregation (ADP-PA) was assessed during baseline hospitalisation and at three, six, and nine months after discharge. Adherence to medication with clopidogrel was defined as the proportion of drug availability based on data from the National Health Fund regarding prescribed drug purchases. Adherence was arbitrarily judged adequate when the proportion exceeded 80%.

Results: According to our hypothesis, ADP-PA in non-adherent patients should be higher at follow-up visits (at least once) as compared with measurement at hospitalisation. Based on the ROC curve analysis, the optimal cut-off point equal to 4 U was defined (p < 0.0001, 95% CI 0.562–0.654; sensitivity: 60.6%, specificity: 57.1%, positive predictive value: 63.3%, negative predictive value: 54.2%). The prevalence of true adherence to medication in groups of high and low probability of adherence defined according to developed criteria amounted 60 (50.8%) and 23 (32.4%) cases, respectively (p = 0.01).

Conclusions: The newly developed method of objective identification of patients with high risk of non-adherence to clopidogrel after MI is easily applicable and cheap, and, despite relatively low sensitivity and specificity, it efficiently differentiates patients with regard to clinical end-points during follow-up.

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Keywords

clopidogrel, ADP-induced platelet aggregation, adherence to medication

About this article
Title

Prediction of high risk of non-adherence to antiplatelet treatment

Journal

Kardiologia Polska (Polish Heart Journal)

Issue

Vol 74, No 1 (2016)

Pages

61-67

Published online

2015-06-18

DOI

10.5603/KP.a2015.0117

Bibliographic record

Kardiol Pol 2016;74(1):61-67.

Keywords

clopidogrel
ADP-induced platelet aggregation
adherence to medication

Authors

Aldona Kubica
Karolina Obońska
Michał Kasprzak
Beata Sztuba
Eliano Pio Navarese
Marek Koziński
Iwona Świątkiewicz
Magdalena Kieszkowska
Małgorzata Ostrowska
Grzegorz Grześk
Jacek Kubica

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