Predictive Validity of a QT_c Interval Prolongation Risk Score in the Intensive Care Unit

Area of Science:

• Cardiology
• Critical Care Medicine
• Clinical Prediction Tools

Background:

• Torsade de pointes is a dangerous heart rhythm linked to QT interval prolongation.
• QT interval prolongation affects 24-61% of critically ill patients.
• A predictive tool can aid monitoring and management in intensive care units (ICUs).

Purpose of the Study:

• To evaluate the predictive validity of the Tisdale et al. Risk Score (TRS).
• To assess the sensitivity, specificity, and likelihood ratios of the TRS in a medical ICU setting.

Main Methods:

• A longitudinal, retrospective cohort study of 264 patients from October 2017 to June 2018.
• Data collected from electronic health records included baseline characteristics and risk factors.
• Primary endpoint was the first occurrence of QT interval prolongation (QTc > 500 ms or increase ≥ 60 ms).

Main Results:

• The TRS demonstrated a sensitivity of 97% for identifying patients at risk.
• Specificity for low-risk patients was 16%.
• Positive and negative likelihood ratios were 1.15 and 0.20, respectively.

Conclusions:

• The TRS is highly sensitive for identifying patients at risk of QT interval prolongation.
• Patients classified as low risk by the TRS can be considered to have minimal risk.
• The tool's low specificity limits its ability to reliably exclude all low-risk patients.