Scientists have long known that some people inherit genetic changes that greatly increase their risk of developing cardiomyopathy, a disease that weakens the heart muscle and can eventually lead to heart failure.
Until recently, finding these genetic variants mainly allowed doctors to warn patients about their future risk. A new international study now suggests that genetic testing could do much more by helping doctors choose treatments that prevent heart failure before symptoms develop.
The research was carried out by investigators from the Mass General Brigham Heart and Vascular Institute together with the Broad Institute of MIT and Harvard. Their findings were published in Nature Medicine.
The researchers focused on dapagliflozin, a medicine originally developed for type 2 diabetes. Besides lowering blood sugar, the drug has been shown to reduce the risk of heart failure in many patients. However, scientists did not know whether people carrying inherited cardiomyopathy variants might receive even greater benefits.
To investigate, the team analyzed DNA samples collected during the large DECLARE-TIMI 58 clinical trial. The study included 12,685 adults with type 2 diabetes. Genetic testing identified 121 participants who carried rare variants known to cause inherited cardiomyopathy.
Participants were followed for just over four years. During this time, heart failure hospitalization occurred in 16% of genetic carriers who received placebo. Among carriers treated with dapagliflozin, the hospitalization rate fell to only 3%.
This translated into roughly an 80% reduction in relative risk. By comparison, participants without these genetic variants still benefited from the drug, but their risk reduction was about 32%.
Importantly, the protective effect was seen both in people who already had heart failure and in those who had not yet developed the disease. This raises the possibility that starting treatment before symptoms appear could delay or even prevent future heart damage in genetically vulnerable people.
Dapagliflozin works by helping the kidneys remove extra glucose and sodium from the body. Researchers believe these effects reduce stress on the heart, improve its efficiency, and lower the chance of fluid buildup that can lead to heart failure.
The study also highlights the rapid growth of precision medicine. Instead of relying only on age, blood pressure, or cholesterol, doctors may increasingly use genetic information to decide which treatments will provide the greatest benefit for each patient.
For people with inherited cardiomyopathy, this could transform care from simply monitoring disease to actively preventing it.
The authors emphasize that important questions remain. Because every participant in this trial had type 2 diabetes, scientists still need to determine whether people without diabetes but carrying the same genetic variants would experience similar protection from dapagliflozin. Additional clinical trials will be required before recommendations can be expanded.
Overall, the findings are highly promising. They suggest that a simple genetic test could identify people who stand to gain the greatest benefit from an already available medicine.
This study provides an excellent example of how genetics and modern drug therapy may work together to prevent serious disease rather than simply treating it after symptoms appear.
If confirmed by future research, this approach could become an important part of preventing heart failure in people with inherited heart disease.
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Source: Mass General Brigham.
