Erectile dysfunction (ED), typically defined as the inability to achieve or maintain an erection enough to achieve satisfactory sexual intercourse, affects a large number of aging U.S. men.

Recent studies have reported that 10 percent of men between 40 and 70 live with severe or complete ED.

Age plays a significant role in the onset and development of ED. Its prevalence increases from 22 percent around the age of 40 to almost 50 percent by the age of 70. 

The most commonly prescribed form of ED medication is the so-called phosphodiesterase type 5 (PDE5) inhibitors, which cause vasodilation in the penis and lungs. On the market, they are sold as Viagra, Levitra, Cialis, and Stendra.

New research  - presented today at the American College of Cardiology's 66th Annual Scientific Session - examines the effect of PDE5 inhibitors on men who have had a heart attack.

For men, the risk of heart disease rises considerably after the age of 45.

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What researchers learned

The team - led by Dr. Daniel Peter Andersson, a postdoctoral researcher at Karolinska Institutet in Sweden - looked at the health records of men aged 80 and under who had been diagnosed and hospitalized with their first heart attack between 2007 and 2013.

The health records were part of a Swedish national database that included every hospital in Sweden.

The patients were followed for an average period of 3.3 years after their initial heart attack. Researchers compared the health outcomes of those who received a prescription for a PDE5 inhibitor or alprostadil - another kind of ED medication that is not a PDE5 inhibitor.

Overall, slightly more than 7 percent of men received a prescription for an ED drug. Of these, 92 percent were prescribed a PDE5 inhibitor and 8 percent obtained a prescription for alprostadil.

After adjusting for risk factors such as diabetes, stroke, and heart failure, the researchers found that men who were prescribed PDE5 inhibitors or alprostadil were 40 percent less likely to be hospitalized for heart failure than men who were not using ED medication. 

Additionally, it appeared that taking PDE5 inhibitors also decreased the mortality risk for patients with a heart attack diagnosis.

The findings indicated a dose-response trend - as more prescriptions for PDE5 inhibitors correlated with a lower risk of premature death - but the authors caution that the study is too small to categorically indicate a dose-response benefit.

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ED medication and heart attacks

The lead author said the findings are significant.

"If you have an active sex life after a heart attack, it is probably safe to use PDE5 inhibitors,” said Andersson in a statement. “This type of erectile dysfunction treatment is beneficial in terms of prognosis, and having an active sex life seems to be a marker for a decreased risk of death [and] a healthy lifestyle, especially in the oldest quartile - those 70 to 80 years old. From the perspective of a doctor, if a patient asks about erectile dysfunction drugs after a heart attack and has no contraindications for PDE5 inhibitors, based on these results you can feel safe about prescribing it."

As the study is observational, the researchers could not establish causality or uncover the mechanism by which ED medication may improve cardiovascular health.

Therefore, Andersson says, it is possible that ED drugs are a marker of an active sex life, which could be the reason why these patients went on to live a healthy, heart disease-free life.

However, the authors note that PDE5 inhibitors were initially designed to treat angina - a type of chest pain that occurs when the heart does not receive enough oxygen-filled blood.

Andersson and team also point out that previous research has linked PDE5 inhibitors with lower blood pressure in the heart’s left ventricle. This makes it easier for the heart to pump blood, and the authors speculate that this could explain why the ED medication is beneficial for people who have had a heart attack. 

Despite this, Andersson deems the results of his research surprising, as ED is normally associated with a higher risk of heart disease in healthy men.

Finally, the authors acknowledge the limitations of their study.

The participants’ socioeconomic status was not accounted for and the research did not consider the impact of untreated ED - or the effect of having a healthy, active, medication-free sex life - on people who had had a heart attack.

In the future, Andersson and colleagues plan to conduct a larger-scale study that includes more health records and more comprehensive data on the participants’ education, marital status, and level of income.