More than 10 million men in the United States are affected by erectile dysfunction (ED), with an estimated 100 million men affected worldwide, according to background information in the article. The risk of erectile dysfunction is related to many factors, including age, smoking, diabetes, heart disease, depression, and hypertension. Because cardiovascular disease and erectile dysfunction share etiologies as well as pathophysiology (endothelial dysfunction) and because of evidence that degree of erectile dysfunction correlates with severity of cardiovascular disease, it has been postulated that erectile dysfunction is a sentinel symptom in patients with cardiovascular disease.
Ian M. Thompson, M.D., of the University of Texas Health Science Center at San Antonio, and colleagues studied a group of men who were assessed for ED and subsequent cardiovascular disease over the course of 7 years. The study included men aged 55 years or older who were randomized to the placebo group (n = 9,457) in the Prostate Cancer Prevention Trial at 221 U.S. centers. Participants were evaluated every 3 months for cardiovascular disease and erectile dysfunction between 1994 and 2003. In analysis, factors at study entry taken into account included age, body mass index, blood pressure, serum lipids, diabetes, family history of heart attack, race, smoking history, current use of antihypertensive medication, physical activity, and quality of life.
Of the 9,457 men randomized to placebo, 8,063 (85 percent) had no cardiovascular disease at study entry; of these men, 3,816 (47 percent) had erectile dysfunction at study entry. Among the 4,247 men without erectile dysfunction at study entry, 2,420 men (57 percent) reported incident erectile dysfunction after 5 years. After adjustment, incident erectile dysfunction was associated with a 25 percent increased risk for subsequent cardiovascular events during study follow-up. For men with either incident or prevalent erectile dysfunction, the increased risk was 45 percent.
"Our analysis of men in the placebo group of this study demonstrates the substantial association between incident as well as prevalent erectile dysfunction and subsequent cardiovascular disease, including angina, myocardial infarction, stroke, and transient ischemic attack," the authors write.
"The implications of this study are substantial. With the availability of effective pharmacotherapy, an increasing number of men are seeking care for erectile dysfunction. It is estimated that more than 600,000 men aged 40 to 69 years in the United States develop erectile dysfunction annually. Our data suggest that the older men in this group have about a 2-fold greater risk of cardiovascular disease than [younger] men without erectile dysfunction. With 70 percent to 89 percent of sudden cardiac deaths occurring in men and with many men not having regular physical examinations, this analysis suggests that the initial presentation of a man with erectile dysfunction should prompt the evaluating physician to screen for standard cardiovascular risk factors and, as appropriate, initiate cardioprotective interventions," they write.
"Our data provide the first evidence, to our knowledge, of a strong association between erectile dysfunction and subsequent development of clinical cardiovascular events. Acknowledging this association over a 5-year period and the high prevalence of vasculogenic/atherogenic etiologies in men of this age, the presenting symptom of erectile dysfunction should prompt an assessment of cardiovascular risk factors and vigorous interventions as appropriate. While a full cardiovascular evaluation is not necessary in response to findings of erectile dysfunction in asymptomatic patients, such findings should prompt diligent observation of at-risk men and reinforces the need for intervention for cardiovascular risk factors," the researchers conclude.
(JAMA.2005; 294:2996-3002. Available pre-embargo to the media at www.jamamedia.org) Editor's Note: This study was supported in part by Public Health Service grants from the National Cancer Institute.