Simple lab test for bone disease linked to risk of death in dialysis patients

Jul 31, 2008

Among patients receiving dialysis for chronic kidney disease (CKD), high levels of alkaline phosphatase—a routinely measured laboratory marker of bone disease—may signal an increased risk of death, reports a study in the November Journal of the American Society of Nephrology (JASN).

"This large epidemiologic study shows, for the first time, a consistent and robust association between a high blood level of alkaline phosphatase and cardiovascular death in thousands of dialysis patients across the United States," comments Kamyar Kalantar-Zadeh, MD, of the University of California Los Angeles, one of the study authors. "If the association between alkaline phosphatase and mortality has a causal link, treatment strategies that reduce alkaline phosphatase levels may improve survival in patients with CKD, and probably in many other patients with chronic diseases and active bone disorders."

The researchers analyzed data on nearly 74,000 hemodialysis patients in DaVita dialysis clinics during a three-year period. Laboratory measurements of alkaline phosphatase level measured in a DaVita laboratory center were analyzed as a possible predictor of mortality risk. In dialysis patients, alkaline phosphatase levels are routinely measured to monitor metabolic bone disease, a common complication of CKD. However, current guidelines do not include specific recommendations or targets for serum alkaline phosphatase in CKD patients.

The results showed that patients with higher alkaline phosphatase levels were at higher risk of death during the three-year follow-up period. After adjustment for a wide range of other risk factors, patients with alkaline phosphatase levels above the upper limit of normal (>120 IU/L) had a 25 percent increase in mortality rate.

The link between alkaline phosphatase and mortality was significant across various subgroups of dialysis patients. Surprisingly, this included patients without hepatitis or other liver diseases, which can also cause increased alkaline phosphatase levels; as well as patients who had normal serum liver function or normal nutritional status, reflected by normal serum albumin levels. In addition, patients whose alkaline phosphatase level increased during the first six months of the study were at higher risk of death over the subsequent two and one-half years.

"In dialysis patients, increased levels of alkaline phosphatase in the blood indicate a so-called high-turnover bone disease, which can happen due to hormonal imbalance in CKD," explains Dr. Kalantar-Zadeh. Previous studies have also found evidence of a link between bone disease and cardiovascular health in CKD patients. "Alkaline phosphatase has recently been shown to be associated with increased vascular calcification in experimental studies," he adds. "Our study shows the clinical manifestations of this association in real-world patients."

The study permits no conclusions as to whether high alkaline phosphatase levels are actually responsible for the increase in mortality risk. Dr. Kalantar-Zadeh concludes, "For the ultimate proof of causation, treatment trials are needed to target high bone turnover diseases to reduce serum alkaline phosphatase effectively, and then to ascertain whether these interventions can improve survival."

Source: American Society of Nephrology

Explore further: What to do with kidneys from older deceased donors?

add to favorites email to friend print save as pdf

Related Stories

A hydrogel that knows when to go (w/ Video)

May 07, 2014

Rice University bioengineers have created a hydrogel that instantly turns from liquid to semisolid at close to body temperature – and then degrades at precisely the right pace.

Nanoparticles reboot blood flow in brain

Aug 23, 2012

A nanoparticle developed at Rice University and tested in collaboration with Baylor College of Medicine (BCM) may bring great benefits to the emergency treatment of brain-injury victims, even those with mild injuries.

Recommended for you

Obese British man in court fight for surgery

Jul 11, 2011

A British man weighing 22 stone (139 kilograms, 306 pounds) launched a court appeal Monday against a decision to refuse him state-funded obesity surgery because he is not fat enough.

2008 crisis spurred rise in suicides in Europe

Jul 08, 2011

The financial crisis that began to hit Europe in mid-2008 reversed a steady, years-long fall in suicides among people of working age, according to a letter published on Friday by The Lancet.

New food labels dished up to keep Europe healthy

Jul 06, 2011

A groundbreaking deal on compulsory new food labels Wednesday is set to give Europeans clear information on the nutritional and energy content of products, as well as country of origin.

Overweight men have poorer sperm count

Jul 04, 2011

Overweight or obese men, like their female counterparts, have a lower chance of becoming a parent, according to a comparison of sperm quality presented at a European fertility meeting Monday.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.