Drugs inducing QTcP
To categorise potential drugs induced QTcP, we adopted the most updated CredibleMeds© (May 18, 2020), and then we subdivided these medications into the following categories (18): 1) known risky category which includes all medications with proven evidences of causing QTcP, and are associated with a potential causing of TdP, 2) possible risky group which encompasses all drugs with significant evidences of causing QTcP, but with insignificant evidences that these medications have a risk of causing TdP, and 3) conditional risk group which includes all medicines with sufficient evidences that confirm possible causing QTcP, and TdP, but only under certain circumstances (e.g. inappropriate dosage, or being in a drug–drug interaction). Minor polypharmacy prescriptions were assumed to contain 2-4 prescribed drugs, and major polypharmacy prescriptions were defined to have ≥ 5 prescribed drugs (30).