Control of CV Risks Improves Male Sexual Function
By John Gever, Senior Editor, Published: September 12, 2011
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
Action Points
Note that avoidance of risk factors and the adoption of healthy lifestyle behaviors is associated with reduction of MI, cardiac death, and stroke but few adhere to all of the tenets of a healthy lifestyle.
Point out that these two studies describe benefits of healthy lifestyle on erectile dysfunction and may lead more individuals to adopt these changes and improve health.
Erectile dysfunction (ED) is a cardiovascular risk factor independent of others, even as interventions leading to improvements in such risk factors also appear to alleviate ED, according to two separate meta-analyses.
In one, pooled data from 12 prospective cohort studies indicated that men with ED had increased risks of 35% to 48% for outcomes including cardiovascular disease, coronary heart disease, and stroke, according to Li-Qiang Qin, MD, PhD, and colleagues at Soochow University in Suzhou, China.
The other meta-analysis, with data from six clinical trials, found that successful lifestyle modifications as well as lipid-lowering statin therapy -- intended to improve conventional cardiovascular risk factors -- led to better sexual function, reported Bhanu Gupta, MD, and colleagues at the Mayo Clinic in Rochester, Minn.
The Chinese study appeared in the Sept. 20 issue of the Journal of the American College of Cardiology, while the Mayo review was published online in Archives of Internal Medicine.
As both research groups observed, an association between ED and cardiovascular disease has been noted previously but whether it was causal -- and, if so, in which direction -- remained unclear.
The new studies do not fully resolve these questions. But Qin and colleagues indicated that their analysis points to ED as an independent risk factor for cardiovascular disease.
Gupta and colleagues, meanwhile, concluded that ED is a lifestyle condition that is amenable to the same interventions known to be effective against other lifestyle-related cardiovascular risk factors.
But neither study examined whether drug treatments or other therapies targeting ED specifically -- such as sildenafil (Viagra) and related drugs -- affect cardiovascular risk.
Qin and colleagues searched for prospective cohort studies that looked for associations between ED and risk of fatal and nonfatal cardiac events, heart failure, peripheral artery disease, stroke, sudden death, or all-cause mortality.
Outcomes including acute MI, angina, and other ischemia were lumped together as "coronary heart disease." In turn, these outcomes plus stroke, cardiac arrest, heart failure, peripheral artery disease, and sudden death were all considered "cardiovascular disease."
They found 12 studies meeting their requirements, with a total of more than 36,000 participants.
After adjusting for covariates when possible, Qin and colleagues calculated the following relative risks for adverse outcomes associated with ED, relative to study participants who did not have ED:
Cardiovascular disease, 1.48 (95% CI 1.25 to 1.74)
Coronary heart disease, 1.46 (95% CI 1.31 to 1.63)
Stroke, 1.35 (95% CI 1.19 to 1.54)
All-cause mortality, 1.19 (95% CI 1.05 to 1.34)
In two of the included studies, the reference group was men with minimal to mild ED rather than no ED at all. But excluding them from the meta-analysis did not change the associations substantially, Qin and colleagues indicated.
Other sensitivity analyses also suggested that the relative risks identified in the primary calculations were robust.
However, the researchers noted that ascertainment of ED, enrollment criteria, and other aspects of the included studies varied considerably. Those studies relying on participants' self-reporting of ED may have underestimated its prevalence "because of embarrassment," Qin and colleagues noted.
The Mayo analysis was considerably smaller. Gupta and colleagues drew on a total of six randomized trials conducted since 2004 -- four testing lifestyle modifications and two in which atorvastatin (Lipitor) therapy was the intervention -- with 740 participants, in which effects on ED were measured.
Despite the small number of participants, pooled data from these studies demonstrated that cardiovascular risk-oriented interventions significantly relieved ED.
With ED outcomes standardized to weighted mean differences in International Index of Erectile Function scores, the overall improvement was 2.66 points (95% CI 1.86 to 3.47), Gupta and colleagues reported.
Dropping the two statin studies from the analysis, which had a total of 143 participants, did not affect the result much -- pooled data from the four lifestyle intervention studies showed improvements in ED scores of 2.40 points (95% CI 1.19 to 3.61).
Interventions in those studies included a number of programs, some stressing diet and others emphasizing physical activity.
The statin studies themselves were harder to interpret. One found a significant improvement in ED scores, whereas the other did not -- but with just 12 participants total, its impact on the pooled analysis was minimal.
Gupta and colleagues said the findings could be translated immediately into clinical practice.
Noting that phosphodiesterase-5 (PDE-5) inhibitor drugs such as sildenafil "are the mainstay of therapy for ED," the researchers indicated that physicians would do well to stress diet and exercise as well.
"Adoption of lifestyle modifications and CV risk factor reduction will provide incremental benefit regardless of PDE-5 inhibitor use," they wrote.
To the extent that ED is itself a cardiovascular risk factor, such interventions could also stave off more serious outcomes.
In an invited commentary accompanying the Mayo review, two other researchers concurred.
Militza Moreno, MD, and Thomas A. Pearson, MD, MPH, PhD, of the University of Rochester, noted that acute cardiovascular events and heart failure have serious negative effects on quality of life, as does ED.
"It may be the motivation to prevent one of these other poor outcomes that tips the balance toward lifestyle change," they wrote.
"Both clinicians and public health practitioners should be reassured that the benefits of their lifestyle modification efforts are overwhelmingly positive and continue to grow," they added.