The Use of QT Prolongation Risk Factor Assessment Tool to Assess the Risk of QT Prolongation in Patients Taking Methadone: An Irish Experience

Abstract

Currently, no tool exists to assist doctors in estimating their patients’ risk of QT prolongation. Methadone is one of many medications which is known to prolong a patient’s QT, and which can lead to Torsades de Pointes and sudden cardiac death. The aim of the study was to design a QT prolongation risk factor assessment tool, for patients taking methadone, which would allow physicians to objectively assess a patient’s risk of QT prolongation. Following a literature review a QT prolongation risk factor assessment tool was created. An audit was then carried out to see what risk factors for QT prolongation were identified prior to use of the tool, in our practice, and then after the tool had been introduced. The introduction of a dedicated QT risk factor assessment tool led to an 61% (39/100 to 100/100) increase in the documentation of individual QT prolongation risk factors in our patients. There was a 100% (4/4) increase in the documentation of risk of QT prolongation in the patient notes, of discussion that risk with patients (4/4), and of the frequency of repeat ECGS (4/4). The introduction of such a QT prolongation risk factor assessment tool in our practice led to an increased awareness of QT prolonging medications, an improvement in the documentation of QT prolonging risk factors and a change in the culture of the practice around medication prescribing and QT prolongation. In patients who are on methadone, a QT prolongation risk factor assessment tool allows for an objective assessment of each patient’s risk of QT prolongation which then allows for measures to be put in place to monitor and address this risk.