If every man with erectile dysfunction were screened for heart disease, more than a million events like heart attack or stroke could be avoided over 20 years and more than $21 billion saved, according to a new estimate.

Treating erectile dysfunction itself would save additional money, adding up to more than $28 billion in savings, the authors project.

Erectile dysfunction (ED) has been tied to heart disease because the risk of both rises with high blood pressure, high cholesterol, diabetes, obesity and smoking, they write in the Journal of Sexual Medicine.

Not all men with ED have ED caused by vascular disease, but some do, said lead author Dr. Alexander W. Pastuszak of Baylor College of Medicine in Houston, Texas.

“If you are able to identify the men with ED caused by vascular disease, which also causes (cardiovascular disease), then you can treat those men and prevent cardiovascular events such as heart disease and stroke,” he told Reuters Health by email.

For the new estimate, the authors reviewed literature on the occurrence of ED among men with cardiovascular disease.

Comparing Medicare reimbursements for cardiovascular risk factor screening to the average cost per acute cardiovascular event, the authors estimated how much increased screening would cost and how much it would save by preventing more severe health problems.

More than 18 million men in the U.S. have ED, more than eight million men have cardiovascular disease, and about two million have both, the authors write.

Men with cardiovascular disease risk factors who begin taking statin medications and otherwise treating their condition reduce their risk of an acute heart event by almost 20 percent over the next five years. Based on that, the authors assumed that screening and treating these men would reduce the number of acute events over the same period by 20 percent.

The study team notes that it costs an average of $138 dollars to screen men with ED for high blood pressure, high cholesterol and diabetes and it would cost the same man more than $11,000 for an acute event like a heart attack.

Over the next 20 years, more than five million men who visit the doctor with ED will likely have undiagnosed high blood pressure, cholesterol or diabetes, the authors project. Screening and treating these men would cost $2.6 billion and prevent 55,000 acute heart events, saving $20.4 billion in treatment expenditures.

Treating the underlying risk factors would eliminate more than a million cases of ED as well, saving an additional $9.7 billion on ED medications over time.

The link between ED and cardiovascular disease was uncovered in 2000, after drugs like Viagra had become available, according to Dr. Charalambos Vlachopoulos of the Cardiovascular Diseases and Sexual Health Unit of Athens Medical School in Greece, who was not involved in the new research.

ED comes from dysfunction of the small arteries of the penis at the level of the blood vessels’ inner lining, he told Reuters Health, and that dysfunction extends to arteries throughout the body.

Most men who have ED and cardiovascular disease start experiencing erectile dysfunction two to three years before a heart event, Vlachopoulos said.

Men with trouble getting or maintaining an erection should visit their doctors and be evaluated for underlying heart risk factors, Pastuszak said. Screening is easy and involves evaluating exercise ability by asking whether men are able to walk a mile on flat land in 20 minutes or climb two flights of stairs in 10 seconds without any chest discomfort, blood tests to check for diabetes and altered blood lipids, and blood pressure measurement, he said.

“Not all people with ED have to undergo a thorough cardiological screening,” Vlachopoulos said. “If they have a higher risk profile, if they have diabetes or hypertension or hypercholesterolemia then they have to consult with a cardiac specialist, especially if they have symptoms like chest pain, fatigue or shortness of breath,” he said.

“Many men are afraid of seeing a doctor and would rather suffer silently,” Pastuszak said. “These men should also know that they shouldn’t be afraid to talk about their ED, and should join the national conversation about ED and the growing number of men who are seeing their physicians for ED and getting treatment not only for their ED but also for the CVD that may be as yet undiagnosed.”

“Finally, and perhaps most importantly, men should know that early diagnosis and treatment of CVD and its risk factors can save them not only money, but can improve their quality of life by preventing more morbid cardiovascular events such as heart attack and stroke,” Pastuszak said.