Everyone has seen the almost never-ending television commercials and advertisements in popular magazines promoting products that are of benefit in the treatment of erectile dysfunction (ED). Although safety concerns regarding the use of such medications in males with known cardiovascular disease (CVD) have been raised in the past, a number of studies have indicated that such concerns may be overstated.
ED, defined by the National Institutes of Health as the “inability to achieve or to maintain an erection for sexual activity,” has long been known to be associated with other CVD conditions such as hypertension, diabetes, and coronary artery disease (CAD, disease that affects the arteries supplying the heart muscle). But only within the past several years has attention been focused on ED as a predictor of CVD or as a sign of progression of an underlying medical condition.
In an important epidemiologic (a study that gathers information concerning age, lifestyle etc) study of impotence, the Massachusetts Male Aging Study, found that around 50% of men 40 to 70 years of age reported at least one episode of complete or partial impotence with 10% reporting complete ED, 25% moderate ED, and 17% minimal ED. The greatest risk factor for ED identified by this study was age. The prevalence of ED ranged from 40% at age 40 to 67% at age 70. Complete ED was found in 5% of men at age 40 and increased to 15% of men at age 70. Modifiable risk factors for ED virtually paralleled those for CVD and included hypertension, smoking, elevated lipid levels in the bloodstream (particularly LDL, the “bad cholesterol) and poorly controlled diabetes.
Although the fact that ED and CVD shared several common risk factors had been demonstrated by several studies, the value of ED as a “marker” or “sentinel event” regarding the occurrences of future cardiovascular events such as heart attack was not evaluated until relatively recently.
[Author’s Note: In the following section the reader will encounter the term “hazard ratio.” The hazard ratio is a valuable statistical tool that determines the risk of some future event by comparing one group (the “control” group, which we can call Group A) with a second group (the “study” group, which will be called Group B). A hazard ratio of 1.00 indicates that the future event occurs at the same frequency within both groups (B / A = 1.0) while a hazard ratio of 0.5 indicates that only half the subjects in Group B will report the same event as those in Group A (B / A = 0.5). Obviously, a hazard ratio greater than 1.0 indicates that some event is more likely to occur in Group B than in Group A (B / A = >1.0).]
In a 2005 study published in the Journal of the American Medical Association (JAMA. 2005; 294:2996-3002) Thompson and associates reported their findings obtained as part of the 9,457 men in the placebo (control) group of the Prostate Cancer Prevention Trial. Of the 4,247 men who did not have ED when they entered the study, 2420 (57%) reported the development of ED (incident ED) in the subsequent 5 years. After adjusting for factors such as age or known CVD risk factors ED was associated with a hazard ratio of 1.25 for the development of new CVD events during the course of the study. For those who either had ED at the start of the study or developed it during the course of the study, the hazard ratio was 1.45. These CVD events included myocardial infarction, stroke, angina, and transient ischemic attack (TIA or “mini-stroke”). In men presenting with incident ED and no prior cardiovascular event, the 7-year estimate of cardiovascular events approached 15%. Based on these findings the authors concluded that ED may be a predictor of cardiovascular events and suggested that, in some cases, ED should prompt a work-up of cardiovascular risk factors.
What Does All This Mean?
The underlying processes responsible in CVD and ED are the same in a majority of cases: atherosclerosis (hardening of the arteries). Since atherosclerosis is a systemic (occurring throughout the body) disease and since erection is dependent on the arterial supply to the penis, there is a definite physiological explanation behind the results of the above study. While further studies will be required to confirm and expand the currently available data, men with a recent development of ED should report this to their health care provider.
As to the safety of currently available medications used in the treatment of ED (sildenafil [Viagra], vardenafil [Levitra], and tadalafil [Cialis]), numerous clinical studies have confirmed that these medications are indeed quite safe to use. The major reported side effects are related to a drop in blood pressure following a sudden change in position (postural hypotension). This drop in blood pressure can be expected to be more pronounced in those men also taking medications to treat hypertension and/or coronary artery disease. Postural hypotension is usually brief and can be avoided by avoiding the previously mentioned sudden change in position.
In summary, ED is practically always due to atherosclerosis that is interfering with blood flow to the penis. Since atherosclerosis in known to be a systemic disease, ED may be an “early warning” sign of future CVD events. A recent onset of ED should be reported to the one’s health care provider for possible further evaluation and testing.
The information presented in this article and its included links is of an informational nature only and is not intended as a recommendation of any changes in the reader’s health care program. Before making any changes in diet, medications, or other treatments the reader is strongly advised to consult with their health care provider.