A Clinical Prediction Tool for Clopidogrel Non-responsiveness in Ischemic Stroke Patients
Jakob Plagenz1, Taqua Tabassum1, Amy Lin1, Whitney Carriveau2, Suhas Bajgur3
1Neurology, 2Medical School, University of North Dakota, 3Sanford Health
Objective:
To develop and evaluate a clinically accessible scoring tool, CLEAR (Clopidogrel Response Evaluation and Risk) Score, for predicting clopidogrel non-responsiveness using non-genetic, routinely collected clinical and laboratory data in patients with ischemic stroke.
Background:
Clopidogrel non-responsiveness is an important but under-recognized cause of recurrent ischemic stroke. P2Y12 platelet function testing is not widely available, and CYP2C19 genetic testing remains underutilized due to cost. A simple, clinically driven prediction score is needed to identify potential clopidogrel non-responders in routine practice.
Design/Methods:
We retrospectively reviewed 61 ischemic stroke patients who underwent P2Y12 platelet function testing. Non-responsiveness was defined as a P2Y12 reaction unit (PRU) ≥195. CLEAR Score was developed by assigning weighted binary points to six clinical variables associated with non-responsiveness: diabetes (A1c ≥7%) 2 points, chronic kidney disease (GFR <60 mL/min) 2 points, proton pump inhibitor (PPI) use 3 points, mean platelet volume (MPV ≥10.5 fL) 2 points, non-smoker status 1 point, and prior ischemic stroke 1 point. Patients were classified as responders or non-responders, and scores were compared using Mann–Whitney U tests. ROC analysis was performed to assess predictive accuracy.
Results:
Among 61 patients (15 non-responders, 46 responders), the median CLEAR Score was significantly higher in non-responders (6.0) compared to responders (3.0). Mean component scores for PPI use (2.4 vs 0.3, p<0.01) and CKD (1.1 vs 0.4, p<0.02) were highest among non-responders. MPV was significantly elevated in non-responders (median 10.5 fL vs 9.4 fL, p=0.0002). Area under the ROC curve (AUC) for CLEAR Score was 0.71, demonstrating good discriminative ability.
Conclusions:
The CLEAR Score is a practical, clinically relevant tool to predict clopidogrel non-responsiveness in ischemic stroke patients. It uses routine clinical and laboratory data to help identify patients who may benefit from alternative antiplatelet therapy, such as ticagrelor. The homogeneity of the study population limits generalizability. Future validation in diverse populations is necessary.
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.