Science & Research

Research on Heart Disease in Women

 

 Drawing of Heart and Blood Vessels
 

Heart disease is the leading cause of death for women. Women often experience heart disease differently than men. For example, men have more heart attacks than women, but women have a higher heart attack death rate. Women experience higher bleeding rates during percutaneous coronary interventions (PCI) performed through femoral arterial access. Women are also more susceptible to drug-induced cardiac arrhythmias.

FDA’s Office of Women’s Health (OWH) supports research to provide valuable insight into sex differences in the diagnosis and treatment of cardiovascular disease. OWH has funded 69 studies (15 ongoing and 54 completed) that examine issues such as QT interval prolongation, cardiotoxicity from breast cancer drugs, and sex differences in various cardiac interventional therapies. The results of the completed studies have led to a better understanding of cardiovascular disease in women and contributed to the development of guidance documents for drug and device development for men and women.


 

QT Prolongation: Research on the Effects of Drugs on Women's Hearth Health

OWH QT Research: Making a Difference

The FDA Office of Women’s Health has been a leader in supporting research to better understand and predict drug-induced heart arrhythmias in women.

 

Heart rate is controlled by electrical signals that pass through the heart each time it contracts and relaxes. These signals make up the heart’s electrical cycle – which is commonly measured by the waves on an electrocardiogram (ECG).  

When the heart’s electrical cycle is abnormal, this can cause irregular heart rhythms (arrhythmias). A type of arrhythmia more common in women than in men is Torsade de Pointes (TdP). TdP events are rare but potentially dangerous and can lead to sudden death. Several drugs have the potential to cause TdP and up to 70% of the drug-induced cases of TdP occur in women.

Almost all drugs that cause TdP prolong the so-called QT-interval on the ECG (which corresponds to the heart’s relaxation phase). Since TdP events are rare, the drug-induced prolongation of the QT-interval on the ECG is used as an indicator for increased risk of TdP.

Since its inception in 1994, the Office of Women’s health has worked with FDA’s other research programs to support studies on drug-induced QT prolongation.

Phase 1: Understanding the Sex Differences

The exact reason for the higher rate of drug-induced TdP in women is unknown. However, a number of factors may play a role in this sex difference including higher drug levels in women due to smaller body size, influence of sex hormones, differences in how drugs are broken down and transported to the heart or greater sensitivity to drugs that cause abnormal heart rhythms. OWH funded studies to understand the mechanism of the sex differences in drug-induced QT prolongation. OWH funded the development of a drug safety signal detection software tool that uses adverse event data from marketed drugs captured in the FDA Adverse Event Safety Reporting system to perform analysis of medical product risks by sex/gender, drug, and organ. This software has the ability to graphically display findings over time to better visualize and recognize drug safety effects in women. The Center for Drug Evaluation and Research is currently using this tool for data mining to respond to post marketing drug safety issues.

 Phase 2: Supporting the Development of FDA Guidance

Building on the previous studies, OWH partially funded additional research on metabolic drug-drug interactions that contribute to QT prolongation and fatal heart arrhythmia. OWH-funded research contributed to new guidelines from FDA in conjunction with the International Council on Harmonization (ICH) on the assessment of the QT prolongation potential of drugs for both men and women. As part of these guidelines, FDA implemented a very comprehensive study requirement for new drugs called the Thorough-QT (TQT) study. 

Since the implementation of the TQT study requirement, no drugs have been withdrawn from the US market due to drug-induced QT prolongation.

 

Phase 3: Improving Prediction and Prevention

Although the current FDA guidelines are very useful for identifying QT prolonging drugs, not all QT prolonging drugs cause TdP. FDA is currently sponsoring studies, funded by the Critical Path Initiative and Office of Women’s Health to better screen for QT-prolonging drugs that have different risk for TdP and to develop methods to prevent it. The research can help potentially improve drug development and safety for both women and men.

 

Page Last Updated: 02/03/2017
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