Hypogonadism in men undergoing artificial urinary sphincter (AUS) implantation significantly increases the risk of cuff erosion, according to the results of a study presented by urologists from UT Southwestern Medical Center, Dallas.
Dallas-Hypogonadism in men undergoing artificial urinary sphincter (AUS) implantation significantly increases the risk of cuff erosion, according to the results of a study presented by urologists from UT Southwestern Medical Center, Dallas.
Interest in investigating an association between hypogonadism and AUS cuff erosion was prompted by a clinical observation that most patients presenting with a cuff erosion had a low serum testosterone level. The study, which included data for 52 patients who underwent AUS implantation between 2007 and 2014, showed in a multivariable regression analysis that hypogonadism was an independent predictor for cuff erosion, increasing the risk by 15-fold.
In addition, findings from a Kaplan-Meier analysis indicated that cuff erosion was likely to occur within 8 years after AUS implantation in any man who was hypogonadal at the time of surgery.
Dr. Hofer“The findings of this study provide useful information to include when counseling men before AUS implantation. Now, further study is needed to determine whether testosterone supplementation prior to surgery will mitigate the increased risk of cuff erosion after AUS implantation in hyogonadal men,” said Matthias D. Hofer, MD, who was a fellow in reconstructive urology, trauma, and prosthetics at UT Southwestern working with Allen Morey, MD, at the time of the study. Study results were presented at the AUA annual meeting in San Diego and subsequently published online in Urology (July 20, 2016).
The study included men presenting consecutively to the clinic over a 2-month accrual period for a routine follow-up visit (n=33) or acutely with cuff erosion (n=19). Mean time to the follow-up visit post-AUS implantation was 2.8 years, and mean time to erosion was nearly 2 years with a range of approximately 1 month to 7 years.
Hypogonadism, defined as testosterone <280 ng/dL, was identified in 29 (55.8%) of the 52 men, but the proportion of men who were hypogonadal was significantly higher among those with cuff erosion compared to those without (17/19, 89.5% vs. 12/33, 36.4%; p<.001) while mean serum testosterone was also significantly lower in the cuff erosion group.
Stratifying men by the absence or presence of hypogonadism showed that the majority of hypogonadal men-58.6% (17/29)-experienced cuff erosion.
“The rate of cuff erosion among normogonadal men was 8.7%, which is consistent with the rate reported in the general population,” said Dr. Hofer, who is now assistant professor of urology at Northwestern University Feinberg School of Medicine, Chicago.
Other comparisons between the men with and without cuff erosions showed no significant differences for mean age, mean cuff size, prior AUS, or history of androgen deprivation therapy. A higher proportion of men in the erosion group had a history of radiation therapy compared to the group without erosion, and the difference bordered on statistical significance (p=.05). Compared with the no erosion group, significantly higher proportions of men with an erosion had coronary artery disease and transcorporal AUS placement. However, multivariable analysis as well as subset analyses showed that hypogonadism was the sole independent risk factor for cuff erosion independent of radiation therapy, coronary artery disease, or prior AUS placement, Dr. Hofer said.
Considering that impairment of vascular flow is the common denominator shared by other independent risk factors for AUS cuff erosion (ie, prior pelvic radiation, prior AUS implantation, and prior urethroplasty), the investigators proposed the mechanism underlying the association between hypogonadism and cuff erosion involves decreased vascularization or angiogenesis leading to corpus spongiosum atrophy that limits the ability of the urethra to resist the pressurized AUS cuff.
“Vascularization and angiogenesis can both be stimulated by androgens via the androgen receptor,” Dr. Hofer said.
Several of Dr. Hofer’s co-authors reported a financial or other relationship with Coloplast, Neotract, Inc., NxThera, Inc., GlaxoSmithKline, Boehringer Ingelheim, Procept, and/or American Medical Systems.
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