During the past few decades, advances in medical research and improvements in treatment and prevention have led to better prognoses for people with cardiovascular disease. They live longer and have a better quality of life.

Still, cardiovascular disease remains a challenging condition not only from a patient perspective—but from a financial perspective, as well.

In 2015, the heart disease mortality rate increased for the first time since 1969, according to the Centers for Disease Control and Prevention. And recent projections from the American Heart Association (AHA) estimate that 45 percent of the U.S. population will have cardiovascular disease by 2035 at a cost of $1.1 trillion, doubling the costs from 2015.

RT International, an independent, non-profit research institute, conducted the research for the AHA, which released the findings on Feb. 14.

The projections updated estimates that the AHA made in 2011. Back then, the AHA noted that 100 million people would have cardiovascular disease by 2030, but that actually occurred 15 years earlier than expected.

For their analysis, researchers from RTI International defined cardiovascular disease as high blood pressure, coronary heart disease, congestive heart failure, stroke, atrial fibrillation and other heart diseases.

In 2015, 102.7 million people in the U.S. (41.2 percent of the population) had at least one cardiovascular disease condition, including 96.1 million with high blood pressure, 16.8 million with coronary heart disease, 7.5 million with stroke, 5.8 million with congestive heart failure and 5.2 million with atrial fibrillation.

By 2035, RTI projects that 131.2 million people will have at least one cardiovascular disease condition, including an additional 27.1 million with high blood pressure, an additional 7.2 million with coronary heart disease, an additional 3.7 million with stroke, an additional three million with congestive heart failure and an additional two million with atrial fibrillation.

From 2015 to 2035, medical costs related to cardiovascular disease are expected to increase 135 percent from $318 billion to $749 billion. During that same 20-year period, indirect medical costs related to cardiovascular disease are expected to increase 55 percent from $237 billion to $368 billion.

Meanwhile, total cardiovascular disease costs are expected to more than triple among adults 80 and older and more than double for adults between 65 and 79 years old.

The RTI researchers mentioned that cardiovascular disease medical costs are already the highest for any medical condition. Medical costs include money spent on medical services and any follow-up costs such as prescription drugs and nursing homes. Indirect costs are also high for people with cardiovascular disease, particularly among those from 45 to 64 years old. Indirect costs include lost days at work due to the disease and lost earnings due to premature death.

What can be done to reverse the trend, or at least slow the growth? The AHA recommends that the National Institutes of Health (NIH) increase its funding for heart and stroke research. As of now, NIH invests 4 percent of its budget on heart disease research, 1 percent on stroke research and 2 percent on other cardiovascular disease research, according to the AHA. The organization also mentioned a renewed emphasis on prevention and expansion of access to high-quality healthcare.

“Our lawmakers should pay close attention to these projections as they deliberate changes to the Affordable Care Act (ACA) and the health care system,” AHA President Steven Houser, PhD, said in a news release. “If we are to avert this looming crisis, we must maintain access to healthcare coverage by protecting the ban on pre-existing conditions and enabling everyone to take advantage of an important weapon against [cardiovascular disease]: prevention. Most importantly, we must invest more funding from the NIH in heart and stroke research, so we can give Americans the treatments and cures they will desperately need in the coming years.”