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NCT Number: NCT07374263

Do QT-Prolonging Drugs Cause Major Adverse Cardiac Events in Hospitalized Adults?

There are 28 non-cardiology medications from multiple families costing more than $13 billion annually in Canada, categorized as 'Known' QT-prolonging medications (QTPmeds) based on very low levels of evidence. The association between many commonly used medications listed as known QTPmeds and actual major adverse cardiac events (MACE) is weak. Meanwhile, QTPmeds-related warnings are ubiquitous in every healthcare setting, triggering 'hard stop' disruption millions of times per day to front line clinicians. Poor quality medication safety alerts are increasingly recognized as a source of inferior patient care and provider burnout which detracts from healthcare sustainability.

In this study, anonymized hospital electronic medical record data from more than 990,000 adult patients across Ontario will be used to compare patients who experience MACE with those who do not, measuring their real-time exposure to QT-prolonging drugs. Additionally, machine-learning techniques will also be used to find which patient or treatment factors best predict risk.

The objectives of this study are to 1) Investigate whether exposure to one or more 'Known' QTPmed is associated with an increased risk of MACE after adjusting for confounders; and 2) Identify predictors and their relative importance for QTPmeds-associated MACE.

In summary, QT-prolonging medications have the potential to cause very serious adverse events, including death. However, it is not sufficiently clear which patients under which circumstances suffer events, or when is QT prolongation a useful surrogate marker for harm. Meanwhile, ubiquitous medication alerts related to QT-prolonging medications are at best imprecise and at worst, misleading, costly and potentially dangerous. Now that data resources are available with the data elements, structure and sample size required to rigorously assess this association, this study will address this question to improve patient safety, provider satisfaction and the cost-effectiveness of care.

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Key information

Conditions

Acquired Long QT Arrhythmias, Cardiac Cardiac Conduction System Disease Cardiovascular Abnormalities Cardiovascular Diseases Congenital Abnormalities Congenital, Hereditary, and Neonatal Diseases and Abnormalities Consciousness Disorders Heart Defects, Congenital Heart Diseases Long QT Syndrome MACE Medication Safety Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Pathologic Processes Pathological Conditions, Signs and Symptoms Signs and Symptoms Syncope Tachycardia Tachycardia, Ventricular Torsades de Pointes Unconsciousness Ventricular Arrhythmias

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

St. Joseph's Healthcare Hamilton, Hamilton, Ontario, Canada

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About this study

This study's investigators have formed the largest hospital electronic medical record (EMR) research network in Canada to be able to address this important patient safety issue. The team's combined use of the Ontario GEMINI network and Epic-Dovetale EMR data has huge power because of the nearly 1 million patients, the rich data including medication exposure, outcomes and risk factor determination that is not available elsewhere, and the development of data structure that allows for future international collaborations.

The investigators plan a nested case-control analysis using the Epic-Dovetale EMR and the GEMINI hospital electronic medical record (EMR) data repository (N > 990,000 eligible adult patients) comparing patients with a MACE to those without a MACE and their relative exposure to one or more Known QTPmed during a hospitalization. In addition, the investigators will do time-varying estimates of the risk of MACE for those patients with periods of Known QTPmed exposure and non-exposure during the same hospitalization. The MACE primary outcome is a QTP-relevant composite of death, non-fatal cardiac arrest, ventricular arrhythmias, and syncope. A second analysis will use machine learning algorithms to predict QTPmeds-associated MACE and determine the relative importance of each predictor.

This project will not only improve patient safety dramatically by improving the accuracy of QTPmeds-related alerts, it will also improve productivity and work satisfaction for thousands of healthcare providers internationally. In addition, the continued expansion and improvement of the largest Canadian hospital EMR research data platform is a huge new opportunity for future high-quality research.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adult patients 18 years of age or older
  • Admitted to St. Joseph's Healthcare Hamilton or GEMINI hospitals between December 2017 and March 2025

Exclusion criteria

  • Patients <18 years old
  • Outpatient encounters

Treatment and study plan

Primary outcomes

  1. Composite of major adverse cardiac events (MACE)

    Time frame: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.

    Time to first MACE during hospitalization, defined as incidence of any of the following: Mortality, non-fatal cardiac arrest, ventricular arrythmia including torsades de pointes, and syncope

Secondary outcomes

  1. Overall Mortality

    Time frame: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.

    In-hospital death

  2. Non-fatal cardiac arrest

    Time frame: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.

    Cardiac arrest based on diagnosis or Code Blue or resuscitation with CPR where the patient survives

  3. Ventricular arrhythmias

    Time frame: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.

    Includes Ventricular fibrillation or tachycardia or torsades de pointes

  4. Syncope

    Time frame: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.

    Syncopal event based on diagnosis - brief loss of consciousness

Study contacts

Contact information is provided by the study sponsor or research team.

Anne M Holbrook, MD,PharmD,MSc,FRCPC

CONTACT

[email protected]

905-522-1155 ext. 35269

Sponsors and collaborators

Lead sponsor

St. Joseph's Healthcare Hamilton

Other

Collaborators

  • Canadian Institutes of Health Research (CIHR)
  • McMaster University

Registry information

Official study title

Do 'Known' QT-prolonging Medications Cause Major Adverse Cardiac Events in Hospitalized Adults? The QTP-MACE Study

Acronym: QTP-MACE

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Jan 28, 2026
Registry last updated
Jan 28, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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