Kidney disease associated with 'benign' prostate obstruction

Jun 29 2005

Men who experience signs and symptoms of a prostate obstruction resulting from benign prostatic hyperplasia (BPH) are three times more likely than other men to develop chronic kidney disease, according to findings of a Mayo Clinic study published in this month's edition of Kidney International.

"This is the first study on the topic to sample the general community," says Andrew Rule, M.D., the Mayo Clinic kidney specialist who conducted the study with epidemiologist Steven Jacobsen, M.D., Ph.D.

"Symptomatic and non-symptomatic men were compared, unlike clinical trials and studies in a urology practice, which tend to represent only symptomatic men."

BPH and chronic kidney disease pose significant health problems in older men. Chronic kidney disease (CKD) occurs when the kidneys cannot rid metabolic wastes from the body or maintain the proper fluid and chemical balances. Eventually, the waste builds up and becomes poisonous to the body. Kidney disease can develop rapidly - in two to three months - or gradually over decades.

Many risks coincide with the development of CKD. "Several studies show men with chronic kidney disease have increased chance of death, hospitalization and cardiovascular events," says Dr. Rule.

The prostate gland is located just below a male's bladder and surrounds the top portion of the urethra, the tube that drains urine from the bladder. "Growth of the prostate gland can lead to a bladder outlet obstruction," says Dr. Rule. "An obstruction of the bladder can cause inability to or discomfort in emptying the bladder, a slowed stream of urine, frequent urges to void during the night or an enlarged, damaged bladder."

"We were surprised at how much kidney disease can be attributed to BPH," says Dr. Jacobsen. "An obstruction on the urethra is like a dam on a river - men can still void, but the constant buildup and pressure will ultimately cause damage." BPH affects about half of men in their 60s and up to 90 percent of men in their 70s and 80s. It is not related to the development of prostate cancer, although causes of BPH tissue growth inside the prostate later in life is unclear. Researchers believe that with age the prostate becomes more susceptible to the effects of hormones, including testosterone.

The most effective way to treat CKD is to care for and manage the underlying disease. "It has been shown that many patients with kidney disease respond to surgical treatments of BPH," says Dr. Rule. "There are also medications to relieve obstructions, by either shrinking the prostate gland or relaxing muscles that contribute to the obstruction."

The recent study surveyed 476 white men, ages 40-79, randomly selected from Olmsted County, Minn. Eventually, the researchers would like to see if similar findings are reproduced among general populations studied at other research centers. Dr. Jacobsen also suggests further research and testing to determine if treating BPH reverses the progression of kidney disease.

Ultimately, the researchers hope the results of the study will encourage both physicians and patients to consider BPH as a factor in kidney disease. "Men with diagnosed BPH may need to be screened to see if this condition is causing kidney damage," says Dr. Jacobsen.