Booster Shots

Oddities, musings and news from the health world

Category: kidney disease

Avastin an effective cancer drug, but it can cause kidney damage in some patients, study finds

June 11, 2010 | 12:46 pm

Avastin is a widely used cancer drug that has been shown to be effective against a variety of tumors, including kidney, bowel, ovarian and lung cancer, but the drug produces more than four times the normal risk of a kidney disease called proteinuria in those who use it, researchers reported Friday. Such problems have already been noted anecdotally, but the new study is the first to document the extent of the problem, showing that it affects more than 2% of those who use the drug. Most experts agree that the increased risk is not a sufficient reason to stop using Avastin, which can prolong life, but the findings reinforce the need for physicians to monitor kidney health in patients receiving it.

Proteinuria is characterized by the release of excess proteins from the blood into urine. It can damage the kidney and impair the effectiveness of cancer treatment.

Dr. Shenhong Wu of Stony Brook University Medical Center in New York and his colleagues analyzed 16 studies using Avastin to treat breast, pancreatic, kidney and other tumors in 12,268 patients. They reported in the Journal of the American Society of Nephrology that proteinuria occurred in 2.2% of the patients taking the drug, 4.79 times the normal risk. The risk was highest in those receiving the greatest amount of the drug. The risk of proteinuria in those with kidney cancer was about 10%. The researchers also found a nearly eightfold increase in the risk of nephrotic syndrome, a group of symptoms that include protein in the urine, low blood protein levels, high cholesterol levels, high triglyceride levels and swelling.

Most experts agreed that the risks were  low enough to not be alarming. But Wu said in a statement that "it is particularly important for cancer specialists to monitor the effects of [Avastin] in patients who have kidney cancer or who are receiving higher doses of the drug."

-- Thomas H. Maugh II


Diabetics should not take high doses of vitamin B, researchers say

April 28, 2010 |  5:59 pm

Diabetics with kidney disease who are taking high doses of B vitamins in an effort to forestall heart attacks should stop taking them immediately because they are potentially very harmful, Canadian researchers reported Tuesday in the Journal of the American Medical Assn. Rather than reducing the risk of heart attack and stroke, the vitamins appear to actually increase it, the researchers said.

An estimated 21 million Americans and 3 million Canadians have either Type 1 or Type 2 diabetes, and it is thought that at least 40% of them will develop diabetic nephropathy, in which the function of the kidneys is impaired. Diabetics typically have above-normal levels of the amino acid homocysteine in their blood, and elevated levels are associated with an increased risk of heart disease. B vitamins normally reduce homocysteine levels, and researchers had also though they would improve kidney function.

A team headed by Dr. David Spence of the University of Western Ontario in London organized a clinical trial in which researchers hoped to demonstrate a benefit from the supplement. They enrolled 238 diabetic patients at five Canadian medical centers. Half received a daily dose of 2.5 milligrams of folic acid, 25 milligrams of vitamin B6 and 1 milligram of vitamin B12 and half received a placebo.

After an average of 32 months, the researchers found that those taking the vitamins had a significantly higher decrease in kidney function, as measured by the  ability to filter toxic wastes from the bloodstream. Moreover, eight people taking the vitamins suffered a heart attack, compared with four taking the placebo; and six taking the vitamins suffered a stroke, compared to one taking the placebo. Spence said he was greatly surprised by the results and initially thought that researchers had mixed up the data. He noted that the vitamins are normally excreted in urine and speculated that kidney damage produced by the diabetes led to a toxic buildup of the supplement in the patients. The B vitamins included in multivitamin supplements should not be a problem, he added.

He said that researchers would have to find a different way to reduce homocysteine levels.

The study was funded by the Canadian Institutes of Health Research and the Kidney Foundation of Canada. The vitamins and placebos were donated by Pan American Laboratories.

-- Thomas H. Maugh II


Ask yourself: 'If I needed a kidney, how much risk would I be willing to take?'

March 25, 2010 |  6:30 pm

Kidney For a person already in need of a kidney transplant, a willingness to accept infection risk can come down to the amount of the infection risk, in this case as it pertains to HIV, the age of the donor -- and how long the patient has been waiting.

The waiting is hard.

Researchers at the University of Pennsylvania asked 175 kidney transplant candidates about their willingness to accept a kidney from a donor who might be at higher risk of viral infection. Most (58.9%) would accept at least some risk.

The results may not surprise. But they're a sobering reflection of a crucial need. And they're worth thinking about: How much risk would you accept? The answer for those not on the wait list may depend on whether they know someone on the wait list.

Here's ...

  •  the study, as it will appear in the Clinical Journal of the American Society of Nephrology.
  •  statistics from the National Kidney and Urologic Diseases Information Clearinghouse on kidney and urologic diseases.
  •  a recent L.A. Times article about the long-term health of people who donate kidneys (at least as good, if not better, than people who don't donate kidneys)
  •  and information from the National Kidney Foundation on how to become a living donor.

-- Tami Dennis

Illustration credit: Jon Conrad / For The Times

 


A possible link between anabolic steroid abuse and kidney damage

November 3, 2009 |  5:03 pm

Abusing anabolic steroids can carry numerous health risks. In a new study of bodybuilders who abused the substance, a link may have been found between that misuse and serious kidney problems.

Ks1k89nc In a study presented recently to the annual meeting of the American Society of Nephrologyin San Diego, researchers looked at a small number of bodybuilders who had documented long-term abuse of anabolic steroids and kidney complications.

Among the 10 men, some had proteinuria, or high levels of protein in the urine, as well as renal insufficiency, or poor kidney function caused by reduced blood flow to the kidneys. Five had full nephrotic syndrome, indicated by proteinuria, low levels of protein in the blood, and high cholesterol. Nine had focal segmental glomerulosclerosis, or scarring in the kidneys.

After they stopped using steroids, almost all of the bodybuilders' kidney problems improved. One study participant, however, developed advanced kidney disease and needed dialysis. Another of the bodybuilders resumed his use of steroids and developed kidney dysfunction again.

Researchers believe that the problems could be related to their substantial gains in muscle mass, which signals the kidneys to step up filtration. That added stress could lead to kidney damage. They also noted that similar organ damage is seen in morbidly obese people, but in bodybuilders it seems to be even more serious.

"Athletes who use anabolic steroids and the doctors caring for them need to be aware of the potentially serious risks to the kidney," said Dr. Leal Herlitz of Columbia University Medical Center and lead author of the study in a news release.

-- Jeannine Stein

 Photo credit: Christopher Furlong / Getty Images


Diet soda may help with kidney stones

April 26, 2009 |  9:00 am

Rarely do health experts admit that drinking soda may be good for you. Here's an exception: People who are prone to kidney stones may develop fewer stones by drinking diet soda.

Dietsoda The body needs to maintain a proper alkaline pH balance for healthy functioning. Increased alkalinity is known to be a factor in the development of kidney stones. A study presented today at the annual meeting of the American Urology Assn. meeting in Linthicum, Md., examined 15 popular diet sodas for their citrate and malate content, substances in soda that may help dissolve kidney stones. They found the sodas probably have enough of these substances to inhibit the formation of calcium stones. The researchers, from UC San Francisco, said Diet Sunkist Orange contained the greatest amount of total alkali and Diet 7-Up had the greatest amount of citrate alkali.

Of course, this doesn't give kidney stone sufferers a license to drink up. Kidney stones may be caused, in part, by dehydration, and people with recurring stones are advised to drink a lot of water.

"This study by no means suggests that patients with recurrent kidney stones should trade in their water bottles for soda cans," said Dr. Anthony Y. Smith, a spokesman for the American Urological Assn., in a news release. "However, this study suggests instead that patients with stone disease who do not drink soda may benefit from moderate consumption."

-- Shari Roan

Photo credit: Eric Boyd  /  Los Angeles Times 



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