Background and importance QTc interval prolongation can lead to Torsades de Pointes (TdP) which can result in sudden cardiac death. Several risk factors (certain drugs and patient related factors) can produce QT prolongation. AzCERT1 categorises these drugs. In our hospital, the pharmacist provides ‘QT advice’ for each prescription of a QT drug with a known risk of TdP (CredibleMeds list KR). In 2019, the pharmaceutical guideline for giving QT advice was adjusted in collaboration with cardiologists.
Aim and objectives To compare the feasibility and clinical relevance of QT advice guided by the original and adapted QT guideline.
Material and methods QT advice provided by the pharmacist was analysed. This retrospective analysis included: number of times QT advice was given according to the original (April 2018 to January 2019) and the adapted guideline (May 2019 to October 2019), number of QT drugs (defined as drugs on the CredibleMeds list KR) per prescription and QTc interval >500 ms (if known). For 1 month (15 May to 14 June 2019), the acceptance rate of the pharmaceutical advice, including the QT advice was registered.
Results Differences between the original and adapted guideline are: (1) threshold for advising an ECG (original: ≥2 prescribed QT drugs or 1 QT drug in combination with a drug that inhibits the metabolism of a QT drug; adapted: ≥1 prescribed QT drug) and (2) definition of a recent ECG (original: maximum 1 year old; adapted: during hospitalisation). If no recent ECG is available or the QTc interval is >500 ms, advice is given to the physician.
The number of times advice was given using the original and adapted guideline were 78 (8 advices/month) and 243 (41 advices/month), respectively. On average, using the adapted guideline, advice related to QTc interval ≥500 ms was given 5 times per month compared with once using the original guideline. The acceptance rate of QT advice was 40% with an overall acceptance rate of 79% for all pharmaceutical advices.
Conclusion and relevance Adapting the QT flow resulted in a fivefold increase in the number of times advice was given in relation to QT. The rather low acceptance rate may be explained by the fact that the pharmacist only selected patients on QT drug prescriptions. To enhance the number of times clinically relevant advice is given, patient related risk factors (hypokalaemia, age, gender, cardiovascular comedications) should be included. It is therefore necessary that personalised risk assessment systems help the pharmacist to identify patients at greatest risk for QT prolongation.
References and/or acknowledgements
Arizona Center for Education and Research on Therapeutics. https://www.crediblemeds.org/
Conflict of interest No conflict of interest