Research links cardiometabolic disorders, urologic disease

September 1, 2009

As research reveals more associations between cardiometabolic disorders and urologic disease, experts are emphasizing the importance of the urologist in detecting cardiometabolic risk factors in patients.

Nearly 25% of U.S. adults have a constellation of abnormalities that can be classified as cardiometabolic disorders (CMD): central adiposity, lipid disorders, hypertension, and elevated blood glucose. The cumulative effect is atherosclerotic plaque and, ultimately, cardiovascular disease. But research has shown that the effects of CMD extend beyond the heart, and may even include the genitourinary system. This article examines the association between CMD and sexual dysfunction in aging men. It is part of a coordinated, interdisciplinary initiative prepared by the ModernMedicine Network of 17 health care publications ( http://www.modernmedicine.com/), including Urology Times. Look for additional articles in our October and November issues. For related online content, see the ModernMedicine Network logo below.

"As urologists, we stand on the front lines of care for men as they age," said Craig S. Niederberger, MD, head of the department of urology at the University of Il-linois, Chicago, who moderated a panel discussion at the AUA annual meeting titled, "Declining Sexual Function in the Aging Male."

A handful of wide-ranging studies have recently made their way into the published literature as well. A study by Kupelian et al revealed increased odds of metabolic disorders and lower urinary tract symptoms in men, a finding the authors say "provides further evidence of common underlying factors between lower urinary tract symptoms and chronic conditions outside the urinary tract" (J Urol 2009; 182:616-25). Preliminary data from Natarajan et al examining obesity specifically suggest that long-term weight loss may decrease the incidence and severity of certain non-oncologic urologic diseases (J Urol 2009; 181:2424-9).

In the area of urologic cancer, Beebe-Dimmer et al report that CMD is associated with prostate cancer risk in African-American men, but not in Caucasian men (Urology 2009; 74:185-90). Data from Galeone et al show direct correlations between levels of glycemic index and glycemic load and renal cell carcinoma risk (Ann Oncol 2009 [Epub ahead of print]).

CMD, ED link established

While the association between CMD and other urologic conditions such as BPH still needs to be elucidated, one disorder in which the link has become "pretty well established" is erectile dysfunction, according to Daniel H. Williams IV, MD, assistant professor of urology at the University of Wisconsin, Madison, and one of the panelists for Dr. Niederberger's panel discussion.

"The primary urological condition that we've seen to which there seems to be some link with cardiometabolic syndrome is erectile dysfunction," Dr. Williams told Urology Times. "There are a number of hypotheses that researchers are investigating, but ultimately the risk factors for cardiometabolic syndrome all lead to endothelial dysfunction and vascular disease, which can manifest early as sexual dysfunction in men; specifically, erectile dysfunction."

While the association between CMD and ED is well documented, the exact nature of the relationship is not certain. Traditionally, it has been the belief that elements of CMD contribute to erectile dysfunction, but the opposite may also be true, Dr. Williams says.

"Erectile dysfunction itself may be one of the early independent signals of future cardiovascular disease," he said.

Age may play a role in determining the connection; in younger men, erectile dysfunction could be a harbinger of cardiac disease, says Ajay Nangia, MD, associate professor of urology at the University of Kansas, Kansas City, who also served as a panelist. Earlier this year, Mayo Clinic researchers reported that the occurrence of ED in younger men "is associated with a marked increase in the risk of future cardiac events, whereas in older men, ED appears to be of little prognostic importance" (Mayo Clin Proc 2009; 84:108-13).

Advanced age is also a confounding factor, however.

"With advancing age, there's more exposure to the components of metabolic syndrome that contribute to sexual dysfunction," Dr. Williams said.

With advancing age also comes a decline in men's testosterone level, Dr. Nangia says. Improving testosterone in men with hypogonadism can address cardiometabolic components, he adds.

The relationship between CMD and ED means that urologists are uniquely positioned to detect cardiometabolic risk factors and may even be the first to detect them in a patient, according to Dr. Williams.

"It's not uncommon that the urologist may be the only doctor that a patient sees on a regular basis. Many men are motivated to seek treatment for their erectile dysfunction, and the urologist may be the only provider that patients see for medical care. We may be the only providers who have the opportunity to screen these men for cardiometabolic risk factors," Dr. Williams said.

Assuming a more primary role may not be possible, however.

"My personal opinion is that we unfortunately don't have enough time to be managing the whole medical picture," Dr. Nangia said, although he notes that he frequently asks overweight patients and those who have signs of CMD if they have been tested for diabetes, low testosterone, lipids, cholesterol, and thyroid function. He also counsels overweight patients with hypertension and smokers that they are more likely to develop erectile dysfunction.

"If they [patients] show up with erectile dysfunction, I will tell them about the risks of insulin resistance," Dr. Nangia said. "I will also tell them about the possibility of needing to have their glucose and other blood work checked."

Both physicians note that they regularly help detect CMD and then refer patients to a primary care physician or cardiologist for treatment, if necessary.

"It may be up to urologists to help identify [cardiometabolic] risk factors and then refer patients to a primary care provider or a cardiovascular specialist to treat those risk factors," Dr. Williams said.

Modern Medicine NETWORK

NEWS & UPDATES
Urology Times and the ModernMedicine Network of publications take an in-depth look at cardiometabolic disorders. Read more about this interdisciplinary initiative at: http://www.urologytimes.com/CMDintro

AUDIO
In this podcast, Dr. Williams and Dr. Nangia discuss the effects of cardiometabolic disorders in aging men. Tune in at: http://www.urologytimes.com/CMDpdocast

COMMUNITY
Dr. Neal Shore asks: Do metabolic disorders matter in urology? Read his blog at: http://www.urologytimes.com/CMDblog