Maximum risk score: 9 points + sum of QT-drugs, Low risk: < 5 points, High risk: ≥ 5 points
*QTc prolongation: QTc ≥ 450 ms for males, ≥ 470 ms for females, or an increase from baseline ECG by ≥ 30 ms.
A cutoff of 5 points revealed a good balance between sensitivity and specificity (58% and 69% respectively), a PPV of 41% and an NPV of 82%. We also performed our calculation after removal of drugs from CredibleMeds list 3 as a trigger for the risk score. Since these drugs were not shown to be significant and were no longer calculated in the risk score, removing them from the list of triggering medications would help reduce the volume of alerts and make our risk score more accurate. This resulted in a sensitivity of 68%, a specificity of 66%, a PPV of 45% and an NPV of 83%. Compared with the DDI warnings, these values are more balanced and may help detect QTc-prolongation while reducing false positive alerts.