Acquired Long QTQTP-MACENCT07374263
Do QT-Prolonging Drugs Cause Major Adverse Cardiac Events in Hospitalized Adults?
An observational study of Acquired Long QT and Ventricular Arrhythmias, run by St. Joseph's Healthcare Hamilton at 2 sites in Canada.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Acquired Long QT, Ventricular Arrhythmias, Torsades de Pointes
- How many people
- 990,000 participants
- Where
- 2 sitesCanada
- Study dates
- 1 Feb 2025to Dec 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: This is a retrospective observational study using de-identified electronic-medical-record data from St. Joseph's Healthcare Hamilton and GEMINI hospitals; no direct participant enrollment or consent is required.
Who may be able to join
- Adult patients 18 years of age or older
- Admitted to St. Joseph's Healthcare Hamilton or GEMINI hospitals between December 2017 and March 2025
Who cannot join
- Patients <18 years old
- Outpatient encounters
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Canada2 sites, 2 recruiting
- Recruiting
St. Joseph's Healthcare Hamilton
Hamilton, Ontario, L8N 1Y3
Anne M Holbrook, 905-522-1155 ext. 35269, cptres@mcmaster.ca
- Recruiting
GEMINI
Toronto, Ontario, M5B 1T8
Amol Verma, 416-360-4000, amol.verma@mail.utoronto.ca
About this study
Official title: Do 'Known' QT-prolonging Medications Cause Major Adverse Cardiac Events in Hospitalized Adults? The QTP-MACE Study
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.
Read more
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.
Read the detailed description
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.
- Conditions
- Acquired Long QT, Ventricular Arrhythmias, Torsades de Pointes, Syncope, Medication Safety, MACE
- Keywords
- Medication safety, QT interval prolongation, Long QT syndrome, Ventricular arrhythmia, Torsades de pointes, Major adverse cardiac events
- Medical subject headings
- Torsades de Pointes, Syncope, Long QT Syndrome, Cardiovascular Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Exposed (Known QTPmeds) | Exposed to a known QTP medication | |
| Unexposed (no known QTP meds) | No exposure to a known QTP medication |
What is being measured
The primary outcome is the main question the study is designed to answer.
Composite of major adverse cardiac events (MACE)
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
Measured: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.
Secondary outcomes (4)
Overall Mortality
In-hospital death
Measured: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.
Non-fatal cardiac arrest
Cardiac arrest based on diagnosis or Code Blue or resuscitation with CPR where the patient survives
Measured: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.
Ventricular arrhythmias
Includes Ventricular fibrillation or tachycardia or torsades de pointes
Measured: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.
Syncope
Syncopal event based on diagnosis - brief loss of consciousness
Measured: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Jan 2026
- Study start1 Feb 2025
- Primary completionDec 2027 (estimated)
- Study completionDec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acquired Long QTStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Retrospective
- Enrolment
- 990,000 participants (estimated)
Sponsor and investigators
- Lead sponsor
- St. Joseph's Healthcare Hamilton
- Sponsor type
- University, hospital or other
- Collaborators
- McMaster University, Canadian Institutes of Health Research (CIHR)
- Responsible party
- Principal investigator, Dr. Anne Holbrook, St. Joseph's Healthcare Hamilton
- Investigators
- Anne M Holbrook, Principal investigator, St. Joseph's Healthcare Hamilton
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07374263
- Sponsor's protocol ID
- CIHR grant # PJT-197768
- Acronym
- QTP-MACE
- Status last verified
- Dec 2025
- First submitted
- 6 Dec 2025
- Last updated
- 28 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: It is not permitted for datasets from Epic-Dovetale and GEMINI to be shared openly as they contain sensitive patient health information. This is based on the data governance policies of the Epic-Dovetale and GEMINI research network as well as its research ethics board-approved study protocols. The data can only be accessed in the secure Epic-Dovetale and GEMINI research environment. Summary analyses will be shareable.
Study at a glance
From the registry record, last updated by the sponsor on 28 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Do 'Known' QT-prolonging Medications Cause Major Adverse Cardiac Events in Hospitalized Adults? The QTP-MACE Study
- ClinicalTrials.gov ID
- NCT07374263
- Acronym / sponsor ID
- QTP-MACE / CIHR grant # PJT-197768
- Conditions
- Acquired Long QT, Ventricular Arrhythmias, Torsades de Pointes, Syncope, Medication Safety, MACE
- Keywords
- Medication safety, QT interval prolongation, Long QT syndrome, Ventricular arrhythmia, Torsades de pointes, Major adverse cardiac events
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 990,000 participants (estimated)
- Lead sponsor
- St. Joseph's Healthcare HamiltonUniversity, hospital or other
- Collaborators
- McMaster University, Canadian Institutes of Health Research (CIHR)
- Study start
- 1 Feb 2025 (actual)
- Primary completion
- Dec 2027 (estimated)
- Study completion
- Dec 2027 (estimated)
- First posted
- 28 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Observational model
- Case-control
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Exposed (Known QTPmeds) | – | –Exposed to a known QTP medication |
| Unexposed (no known QTP meds) | – | –No exposure to a known QTP medication |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- This is a retrospective observational study using de-identified electronic-medical-record data from St. Joseph's Healthcare Hamilton and GEMINI hospitals; no direct participant enrollment or consent is required.
Key inclusion criteria (2 listed)
- Adult patients 18 years of age or older
- Admitted to St. Joseph's Healthcare Hamilton or GEMINI hospitals between December 2017 and March 2025
Key exclusion criteria (2 listed)
- Patients <18 years old
- Outpatient encounters
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
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
4 secondary outcomes
Overall Mortality
Time frame: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.
Non-fatal cardiac arrest
Time frame: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.
Ventricular arrhythmias
Time frame: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.
Syncope
Time frame: From first exposure to the end of hospitalization, which would typically be up to 4 weeks follow-up.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Jan 2026.
- Individual participant dataSharing planned: No. It is not permitted for datasets from Epic-Dovetale and GEMINI to be shared openly as they contain sensitive patient health information. This is based on the data governance policies of the Epic-Dovetale and GEMINI research network as well as its research ethics board-approved study protocols. The data can only be accessed in the secure Epic-Dovetale and GEMINI research environment. Summary analyses will be shareable.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Anne M Holbrook principal investigator
St. Joseph's Healthcare Hamilton
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Acquired Long QT and Ventricular Arrhythmias, run by St. Joseph's Healthcare Hamilton at 2 sites in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 28 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Anne M Holbrook, MD,PharmD,MSc,FRCPC (905-522-1155 ext. 35269, cptres@mcmaster.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Jan 2026.