Recent kidney policy changes have not created racial disparities in care

Recent policy and guideline changes related to the care of patients with kidney failure have not created racial disparities, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN). Such studies are needed to ensure that all patients continue to receive the highest quality of care after such changes are implemented.

In 2011, the End-Stage Renal Disease Prospective Payment System went into effect, which changed the way dialysis facilities were paid for care related to kidney failure. That same year, changes were also made to dosing guidelines for anemia drugs, which are often taken by patients with kidney disease.

Marc Turenne, PhD (Arbor Research Collaborative for Health) and his colleagues assessed the effects of these changes on racial disparities in the management of anemia and mineral metabolism in 7384 kidney failure patients at 132 dialysis facilities.

The researchers observed no meaningful overall differences by race regarding the rates of change of management practices or laboratory measures from August 2010 to December 2011. For example, declines in average doses of anemia drugs and average hemoglobin levels were similar for African American patients and patients of other races. Overall trends in injectable vitamin D doses and parathyroid hormone levels, which are key indicators of mineral metabolism care, were also similar for both race groups during this time.

“These early results are encouraging, and they indicate that recent policy and regulatory changes that are intended to improve the efficiency and quality of care for patients with kidney failure have not caused disparities by race in areas of care where there have historically been racial differences,” said Dr. Turenne. “As policy-makers look for ways to make the delivery of health care services more affordable, it’s important to ensure that patients are still receiving the highest quality of care.”

Highlight

After the implementation of a new payment system for kidney failure care and changes to dosing guidelines for anemia drugs, there were no meaningful differences by race regarding changes in management practices or laboratory measures among dialysis patients.

At the end of 2009, more than 871,000 people in the United States were being treated for kidney failure.

http://www.medicalnewstoday.com/releases/283774.php

 

 

Potential blood test for disorder that can accelerate organ failure in kidney transplant recipients

Researchers at UC San Francisco and Rush University Medical Center, Chicago, may have found a predictor for a disorder affecting kidney transplant recipients that can accelerate organ failure, a discovery that eventually could allow for customized therapies and improved patient selection for transplant.

The study of focal segmental glomerulosclerosis (FSGS), a devastating form of kidney disease, is in the journal Science Translational Medicine. Research was conducted by an international study team, with Necker Hospital in Paris and UCSF joint lead authors and Rush University Medical Center and UCSF joint senior authors.

“This is a new blood test to monitor patients before kidney transplant and predict who may have recurrence of FSGS, thereby preventing loss of kidneys,” said co-senior author Minnie Sarwal, MD, PhD, professor of transplant surgery at UCSF.

In the kidneys, the glomeruli serve as filters, helping rid the body of unnecessary or harmful substances. After a kidney transplant, scar tissue can form on parts of the donated kidney glomeruli, causing FSGS.

Kidney transplant patients with FSGS face a high risk of disease recurrence, 20-40 percent after a first transplant and up to 80 percent after a second. Its causes are largely unknown and may include circulating proteins and antibodies. Recurrence is managed by immunosuppressive drugs along with current standards of treatment that include salt restriction, diuretics and steroids, plasma filtration, and immunoadsorption.

“The clinical and economic impact of changing the course of FSGS recurrence has far-reaching implications,” the study authors wrote. “These include improved graft survival, reduced patient morbidity, reduced cost of salvage therapies including dialysis, and the preservation and increased availability of transplant organs.”

In their research, Sarwal and her colleagues used high-density protein tests to process 141 serum samples from 98 patients (64 with FSGS) before and one year after transplant surgery. Patients were from four transplant programs in the United States and Europe.

Of the approximately 9,000 antigens (foreign or toxic substances) screened, the tests identified antibodies against 789 antigens that were significantly increased in patients at risk for FSGS. In further studies using mice, the antibody levels in a protein called CD40 had 78 percent prediction accuracy for FSGS, while a panel of seven out of 10 antibodies that target glomerular antigens increased the accuracy to 92 percent.

As a result, a pre-transplant antibody panel that included anti-CD40 antibodies – named FAST for “FSGS Antibody Screen for Transplant” – could be a good predictor for FSGS. Using FAST, the researchers even learned the antibody signature in FSGS patients remains a year after transplant, despite intensified immunosuppressive therapy and plasma exchange.

“We found that during FSGS recurrence, the antibody binding to the CD40 protein in the podocytes of the kidney drives injury to the kidney’s filtering unit with leakage of protein and scar tissue, and blocking this CD40 antibody appears to reverse injury,” Sarwal said. “This suggests CD40 blockade in kidney transplant patients may help cure the disease. This drug already is beneficial for organ transplants due to its immunosuppressive properties, so it would be a very attractive new drug for FSGS recurrence prevention in kidney transplants.”

Podocytes are cells in the Bowman’s capsule of the kidneys that wrap around the glomerulus capillaries. The Bowman’s capsule performs the first step in filtering blood to form urine.

Another study highlight is the observation that patient-derived antibodies against CD40 functionally cooperate with a previously identified culprit of FSGS called soluble urokinase plasminogen activator receptor (suPAR). Co-injection of patient-derived CD40 anti-autobodies and suPAR caused enhanced kidney filter failure more than each component did by itself.

“This is an important, novel discovery of a pathogenic antibody synergizing effects with a circulating factor that further sheds light on the enigmatic problem in kidney transplantation, i.e., FSGS recurrence,” said study co-senior and co-correspondent author Jochen Reiser, MD, PhD, Ralph C. Brown MD professor and Chairman of Medicine at Rush University Medical Center.

According to Sarwal, additional study of the FAST panel is needed, followed by a clinical trial in collaboration with a pharmaceutical company of an anti-CD40 drug.

“We want to predict FSGS recurrence before we put a kidney in,” said Sarwal, who conducted the research while at Stanford University and has since moved her entire lab to UCSF. “We then can treat the high-risk patients with a new drug to possibly prevent disease.”

http://www.medicalnewstoday.com/releases/283365.php

 

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Administration of drug for kidney injury after cardiac surgery does not reduce need for dialysis

Among patients with acute kidney injury after cardiac surgery, infusion with the antihypertensive agent fenoldopam, compared with placebo, did not reduce the need for renal replacement therapy (dialysis) or risk of death at 30 days, but was associated with an increased rate of abnormally low blood pressure, according to a study published in JAMA. The study is being posted early online to coincide with its presentation at the European Society of Intensive Care Medicine annual congress.

More than 1 million patients undergo cardiac surgery every year in the United States and Europe. One of its most common complications is acute kidney injury. Because of its hemodynamic effects, fenoldopam has been widely promoted for the prevention and therapy of acute kidney injury, with apparent favorable results in cardiac surgery. However, the absence of a definitive trial leaves clinicians uncertain as to whether fenoldopam should be prescribed after cardiac surgery to prevent deterioration in kidney function, according to background information in the article.

Tiziana Bove, M.D., of the IRCCS San Raffaele Scientific Institute, Milan, Italy, and colleagues randomly assigned 667 patients admitted to intensive care units after cardiac surgery with early acute kidney injury to receive fenoldopam infusion (338 patients) or placebo (329 patients). The study was conducted from March 2008 to April 2013 in 19 cardiovascular intensive care units in Italy.

The study was stopped for futility as recommended by the safety committee after a planned interim analysis. Acute kidney injury progressed to treatment with dialysis in 69 of 338 patients (20 percent) in the fenoldopam group and 60 of 329 patients (18 percent) in the placebo group. Thirty-day mortality was 78 of 338 (23 percent) in the fenoldopam group and 74 of 329 (22 percent) in the placebo group. The number of patients experiencing hypotension (abnormally low blood pressure) during study drug infusion was 85 (26 percent) in the fenoldopam group vs 49 (15 percent) in the placebo group.

“Given the cost of fenoldopam, the lack of effectiveness, and the increased incidence of hypotension, the use of this agent for renal protection in these patients is not justified,” the authors conclude.

http://www.medicalnewstoday.com/releases/283111.php

 

 

FDA allows marketing of the first test to assess risk of developing acute kidney injury

The U.S. Food and Drug Administration has allowed marketing of the NephroCheck test, a first-of-a-kind laboratory test to help determine if certain critically ill hospitalized patients are at risk of developing moderate to severe acute kidney injury (AKI) in the 12 hours following the administration of the test. Early knowledge that a patient is likely to develop AKI may prompt closer patient monitoring and help prevent permanent kidney damage or death.

The kidneys filter waste and extra water out of the blood and are important in controlling blood pressure and other essential body functions. When kidneys are not functioning properly, waste builds up in the body and can cause serious health problems.

AKI is a sudden decline in kidney function, often without early signs or symptoms, following an injury to the kidney caused by a co-existing disease, infection, or other condition. AKI can cause fluid to build up in the body, chest pain, muscle weakness, and permanent kidney damage or chronic kidney disease (the gradual loss of kidney function). Critically ill patients are the most at risk for AKI, particularly patients who meet certain factors such as advanced age,diabetes and high blood pressure.

Current laboratory tests can only assess whether a patient may already have AKI; often, the patient has progressed to moderate to severe AKI before the test results confirm the clinical diagnosis. NephroCheck detects the presence of insulin-like growth-factor binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases (TIMP-2) in the urine, which are associated with acute kidney injury. Within 20 minutes, the test provides a score based on the amount of the proteins present that correlates to the patient’s risk of developing AKI within 12 hours of the test being performed. No other tests currently on the market are FDA-approved or cleared to assess the risk of developing AKI in at-risk patients.

“Early assessment and timely treatment for AKI can help prevent kidney damage and potential associated complications,” said Alberto Gutierrez, director of the Office of In Vitro Diagnostics and Radiological Health at the FDA’s Center for Devices and Radiological Health. “The NephroCheck provides health care providers with a quick, validated method of assessing a patient’s AKI risk status which may inform patient management decisions.”

The FDA reviewed the data for NephroCheck through the de novo premarket review pathway, a regulatory pathway for some low- to moderate-risk medical devices that are not substantially equivalent to an already legally marketed device.

The FDA’s review included two clinical studies evaluating the test’s safety and effectiveness. The two studies compared the clinical diagnoses of more than 500 critically ill subjects at 23 hospitals to NephroCheck test results. NephroCheck accurately detected 92 percent of AKI patients in one study and 76 percent in the other. In both studies, NephroCheck incorrectly gave a positive result in about half of patients without AKI.

The NephroCheck Test System is manufactured by Astute Medical based in San Diego, California.

http://www.medicalnewstoday.com/releases/282150.php

 

 

Catheter-associated urinary tract infections significantly reduced by electronic alerts

A Penn Medicine team has found that targeted automated alerts in electronic health records significantly reduce urinary tract infections in hospital patients with urinary catheters. In addition, when the design of the alert was simplified, the rate of improvement dramatically increased.

The alerts help physicians decide whether their patients need urinary catheters in the first place and then alert them to reassess the need for catheters that have not been removed within a recommended time period. The electronic alert, developed by medical researchers and technology experts at the Perelman School of Medicine at the University of Pennsylvania, is the subject of a study published in the September issue of Infection Control and Hospital Epidemiology.

Approximately 75 percent of urinary tract infections acquired in the hospital are associated with a urinary catheter, which is a tube inserted into the bladder through the urethra to drain urine. According to the Centers for Disease Control and Prevention, 15 to 25 percent of hospitalized patients receive urinary catheters during their hospital stay. As many as 70 percent of urinary tract infections in these patients may be preventable using infection control measures such as removing no longer needed catheters resulting in up to 380,000 fewer infections and 9,000 fewer deaths each year.

“Our study has two crucial, applicable findings,” said the Penn study’s lead author Charles A. Baillie, MD, an internal medicine specialist and fellow in the Center for Clinical Epidemiology and Biostatistics at Penn Medicine. “First, electronic alerts do result in fewer catheter-associated urinary tract infections. Second, the design of the alerts is very important. By making the alert quicker and easier to use, we saw a dramatic increase in the number of catheters removed in patients who no longer needed them. Fewer catheters means fewer infections, fewer days in the hospital, and even, fewer deaths. Not to mention the dollars saved by the health system in general.”

In the first phase of the study, two percent of urinary catheters were removed after an initial “off-the-shelf” electronic alert was triggered (the stock alert was part of the standard software package for the electronic health record). Hoping to improve on this result in a second phase of the study, Penn experts developed and used a simplified alert based on national guidelines for removing urinary catheters they had previously published with the CDC. Following introduction of the simplified alert, the proportion of catheter removals increased more than seven-fold to 15 percent.

The study also found that catheter associated urinary tract infections decreased from an initial rate of .84 per 1,000 patient days to .70 per 1,000 patient-days following implementation of the first alert and .50 per 1,000 patient days following implementation of the simplified alert. Among other improvements, the simplified alert required two mouse clicks to submit a remove-urinary-catheter order compared to seven mouse clicks required by the original alert.

The study was conducted among 222,475 inpatient admissions in the three hospitals of the University of Pennsylvania Health System between March 2009 and May 2012. In patients’ electronic health records, physicians were prompted to specify the reason (among ten options) for inserting a urinary catheter. On the basis of the reason selected, they were subsequently alerted to reassess the need for the catheter if it had not been removed within the recommended time period based on the reason chosen.

Women’s health units had the highest proportion of alerts that led to a remove-urinary-catheter order and critical care units saw the lowest proportion of alerts leading to a remove order.

“As more hospitals adopt electronic health records, studies such as ours can help point the way toward improved patient care,” said senior author Craig Umscheid, MD, MSCE, assistant professor of Medicine and Epidemiology and director of Penn’s Center for Evidence-based Practice. “Thoughtful development and deployment of technology solutions really can make a difference. In this study, we learned that no two alerts are alike, and that changes to an alert’s usability can dramatically increase its impact.”

Several studies have already shown that reminder systems to limit the use and duration of urinary catheters can lower catheter infection rates. However, the majority of these have used non-computerized reminders, such as written reminders or stickers. The current Penn study is one of the largest to examine the impact of electronically generated alerts. In addition to the size of the study, a second strength is its multi-year duration. Most prior studies relied on a brief study period, and several studies observed an increase in catheter use when the relatively brief intervention had ended.

http://www.medicalnewstoday.com/releases/281479.php

 

 

 

Atypical antipsychotic drug use increases risk for acute kidney injury

Atypical antipsychotic drug use is associated with an increased risk for acute kidney injury (AKI) and other adverse outcomes, according to a study being published in Annals of Internal Medicine.

Each year, millions of older adults are prescribed atypical antipsychotic drugs (quetiapine, risperidone, and olanzapine) to manage behavioral symptoms of dementia, which is not an approved indication. This type of off-label use has raised safety concerns, as these atypical antipsychotics are known to cause AKI. Researchers compared medical records for 97,777 adults aged 65 or older who received a new outpatient prescription for an oral atypical antipsychotic drug against a matched cohort of patients who had not received such a prescription to determine the risk for AKI and other adverse outcomes.

Persons who had received a prescription for any three atypical antipsychotic drugs in the previous 90 days had an elevated risk for hospitalization with AKI. The drugs were also associated with increased risk for hypotension, acute urinary retention, and death. The findings support current safety concerns regarding the use of these drugs in older adults.

Study: Atypical Antipsychotic Drugs and the Risk for Acute Kidney Injury and Other Adverse Outcomes in Older Adults: A Population-Based Cohort Study, Y.J. Hwang, S.N. Dixon, J.P. Reiss, R. Wald, C.R. Parikh, S. Gandhi, S.Z. Shariff, N. Pannu, D.M. Nash, F. Rehman, and A.X. Garg, Annals of Internal Medicine, doi: 10.7326/M13-2796, published 18 August 2014.

http://www.medicalnewstoday.com/releases/281206.php

 

 

Enzyme lost in 100 percent of kidney tumors analyzed

In an analysis of small molecules called metabolites used by the body to make fuel in normal and cancerous cells in human kidney tissue, a research team from the Perelman School of Medicine at the University of Pennsylvania identified an enzyme key to applying the brakes on tumor growth. The team found that an enzyme called FBP1 – essential for regulating metabolism – binds to a transcription factor in the nucleus of certain kidney cells and restrains energy production in the cell body. What’s more, they determined that this enzyme is missing from all kidney tumor tissue analyzed. These tumor cells without FBP1 produce energy at a much faster rate than their non-cancer cell counterparts. When FBP1 is working properly, out-of-control cell growth is kept in check.

The new study, published online this week in Nature, was led by Celeste Simon, PhD, a professor of Cell and Developmental Biology and the scientific director for the Abramson Family Cancer Research Institute at Penn.

Clear cell renal cell carcinoma (ccRCC), the most frequent form of kidney cancer, is characterized by elevated glycogen (a form of carbohydrate) and fat deposits in affected kidney cells. This over-storage of lipids causes large clear droplets to accumulate, hence the cancer’s name.

In the last decade, ccRCCs have been on the rise worldwide. However, if tumors are removed early, a patient’s prognosis for five-year survival is relatively good. If expression of the FBP1 gene is lost, patients have a worse prognosis.

“This study is the first stop in this line of research for coming up with a personalized approach for people with clear cell renal cell carcinoma-related mutations,” says Simon, also an investigator with the Howard Hughes Medical Institute.

A Series of Faulty Reactions

The aberrant storage of lipid in ccRCC results from a faulty series of biochemical reactions. These reactions, called the Kreb’s cycle, generate energy from carbohydrates, fats, and proteins in the form of ATP. However, the Kreb’s cycle is hyperactive in ccRCC, resulting in enhanced lipid production. Renal cancer cells are associated with changes in two important intracellular proteins: elevated expression of hypoxia inducible factors (HIFs) and mutations in the von Hippel-Lindau (VHL) encoded protein, pVHL. In fact, mutations in pVHL occur in 90 percent of ccRCC tumors. pVHL regulates HIFs, which in turn affect activity of the Kreb’s cycle.

Although much is already known about metabolic pathways and their role in cancer, there are still important questions to be answered. For example, kidney-specific VHL deletion in mice does not elicit clear cell-specific tumor formation, suggesting that additional mechanisms are at play. Toward answering that hunch, recent large-scale sequencing analyses have revealed the loss of several epigenetic enzymes in certain types of ccRCCs, suggesting that changes within the nucleus also account for kidney tumor progression.

To complement genetic studies revealing a role for epigenetic enzymes, the team evaluated metabolic enzymes in the 600-plus tumors they analyzed. The expression of FBP1 was lost in all kidney cancer tissue samples examined. They found FBP1 protein in the cytoplasm of normal cells, where it would be expected to be active in glucose metabolism. But, they also found FBP1 in the nucleus of these normal cells, where it binds to HIF to modulate its effects on tumor growth. In cells without FBPI, the team observed the Warburg effect – a phenomenon in which malignant, rapidly growing tumor cells go into overdrive, producing energy up to 200 times faster than their non-cancer-cell counterparts.

This unique dual function of FBP1 explains its ubiquitous loss in ccRCC, distinguishing FBP1 from previously identified tumor suppressors that are not consistently inhibited in all tumors. “And since FBP1 activity is also lost in liver cancer, which is quite prevalent, FBP1 depletion may be generally applicable to a number of human cancers,” notes Simon.

Next steps, according to the researchers, will be to identify other metabolic pathways to target, measure the abundance of metabolites in kidney and liver cancer cells to determine FBP1’s role in each, and develop a better mouse model for preclinical studies.

Picture Credit: Credit: Bo Li and Brian Keith, Perelman School of Medicine, University of Pennsylvania.

http://www.medicalnewstoday.com/releases/279893.php

 

 

 

Nanoparticles used to enhance chemotherapy

University of Georgia researchers have developed a new formulation of cisplatin, a common chemotherapydrug, that significantly increases the drug’s ability to target and destroy cancerous cells.

Cisplatin may be used to treat a variety of cancers, but it is most commonly prescribed for cancer of the bladder, ovaries, cervix, testicles and lung. It is an effective drug, but many cancerous cells develop resistance to the treatment.

Shanta Dhar, assistant professor of chemistry in the UGA Franklin College of Arts and Sciences, and Rakesh Pathak, a postdoctoral researcher in Dhar’s lab, constructed a modified version of cisplatin called Platin-M, which is designed to overcome this resistance by attacking mitochondria within cancerous cells. They published their findings recently in the Proceedings of the National Academy of Sciences.

“You can think of mitochondria as a kind of powerhouse for the cell, generating the energy it needs to grow and reproduce,” said Dhar, a member of the UGA Cancer Center and principal investigator for the project. “This prodrug delivers cisplatin directly to the mitochondria in cancerous cells. Without that essential powerhouse, the cell cannot survive.”

Sean Marrache, a graduate student in Dhar’s lab, entrapped Platin-M in a specially designed nanoparticle 1,000 times finer than a human hair that seeks out the mitochondria and releases the drug. Once inside, Platin-M interferes with the mitochondria’s DNA, triggering cell death.

Dhar’s research team tested Platin-M on neuroblastoma – a cancer commonly diagnosed in children-that typically originates in the adrenal glands. In preliminary experiments using a cisplatin-resistant cell culture, Platin-M nanoparticles were 17 times more active than cisplatin alone.

“This technique could become a treatment for a number of cancers, but it may prove most useful for more aggressive forms of cancer that are resistant to current therapies,” said Pathak.

Both Dhar and Pathak caution that their experimental results are preliminary and they must do more work before Platin-M enters any clinical trials. However, their early results in mouse models are promising, and they are currently developing safety trials in larger animals.

“Cisplatin is a well-studied chemotherapy, so we hope our unique formulation will enhance its efficacy,” said Dhar, who is also a member of UGA’s Nanoscale Science and Engineering Center, Center for Drug Discovery, and Regenerative Bioscience Center. “We are excited about these early results, which look very promising.”

 

http://www.medicalnewstoday.com/releases/279303.php

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“Big data” technique improves monitoring of kidney transplant patients

A new data analysis technique could radically improve monitoring of kidney transplant patients, according to new research published this week in PLOS Computational Biology.

The research, carried out by a team comprising physicists, chemist and clinicians at the University of Leeds, provides a method for making sense out of the huge number of clues about a kidney transplant patient’s prognosis contained in their blood.

By applying a sophisticated “big data” analysis to the samples, scientists were able to process hundreds of thousands of variables into a single parameter to indicate how a kidney transplant was faring. This allowed them to predict poor function of a kidney after only two days in cases that may not have been previously detected as failing until weeks after transplant.

These extra few days are vital in the early stages after transplant and would give doctors a better chance to intervene to save the transplant and improve patient recovery periods. In some cases, the team were able to predict failure from patients’ blood samples taken before the transplant operation.

Dr Sergei Krivov, in the University of Leeds’ Astbury Center, said: “If you put a blood sample through Nuclear Magnetic Resonance analysis you get data down to the molecular level. You can identify chemical fingerprints left behind by specific cellular processes and you get a very large number of different parameters in those samples that vary with the outcome for a patient.

“These are vital clues. But, if you have got thousands of variables all moving in different ways in a complex system, how does a doctor bring all that information together and decide what to do? It is not possible to do this with the human mind; there are just too many variables. We have to do it with computers and find a way to weigh those variables and produce an intelligible output describing where, overall, the patient is heading.”

The study, which analysed data from daily blood samples from 18 patients immediately before and in a week-long period after kidney transplants, showed that it was possible to pick out pieces of information that varied with the overall likelihood of a patient either rejecting a kidney or recovering kidney function.

Given enough data, the technique could even be used to quantify very complex and extended processes affecting the whole population.

http://www.medicalnewstoday.com/releases/278531.php

 

 

 

Increased risk of rare, deadly condition faced by obese, older, Caucasian women on dialysis

Obese, Caucasian females over age 50 with diabetes and on dialysis because their kidneys have failed are among those at highest risk for the rare and deadly condition calciphylaxis, according to an analysis of the United States Renal Data System.

Calciphylaxis occurs when calcium and phosphorus bind to form a biological cement that blocks and inflames small blood vessels, putting patients at risk for major infection and skin ulcers as well as patches of dying skin, said Dr. Lu Huber, nephrologist at the Medical College of Georgia at Georgia Regents University.

“It’s all about balance, and our kidneys help regulate that balance,” said Huber, who scoured the national database of 2.1 million patients with failed kidneys to better define incidence and risk factors with the goal of better identifying and managing those at highest risk.

Her findings were cited as one of eight best abstracts submitted to the 51st European Renal Association – European Dialysis and Transplant Association Congress in Amsterdam.

Huber found the condition occurred in 459, or 0.02 percent, of the patients, who were mostly white, older women on traditional hemodialysis, where an external machine filters the total blood volume typically three times a week rather than the continuous efforts of healthy kidneys.

The median time from the first dialysis treatment to a diagnosis of calciphylaxis was less than four years, median survival time was 176 days, and 50 percent of deaths were within 87 days. Being over age 65, Caucasian, and diabetic are significant risk factors for death from calciphylaxis.

“We are not completely sure why calciphylaxis happens, but mostly it’s in dialysis patients,” Huber said. While dialysis is literally a lifesaver, it does not completely replace all the filtering work of the kidney, never mind other major functions, such as making the active form of vitamin D, Huber said. Vitamin D increases absorption of calcium, which is essential to strong bones and teeth as well as muscle function, including the heart.

Physicians give patients vitamin D while they are receiving dialysis to keep bone strong. Ironically, vitamin D also increases absorption of phosphorus, which, without functioning kidneys, begins to accumulate in the blood.

“In end-stage renal disease, we tend to see low calcium and high phosphorus,” Huber said. The dysregulation somehow prompts the two to bind in the blood and ‘basically make cement,” Huber said. The material deposits in small blood vessels, valves and soft tissue, contributing to the vascular complications of life on dialysis.

“When we do X-rays of patients, their small vessels actually light up because of the calcium/phosphorus deposition,” Huber said. With the calcium-phosphorus deposition, vessels quickly become stiff and narrowed, which leads to inadequate blood supply, contributing to tissue death, and paving the way for infection.

To try and balance things out, all dialysis patients take phosphorus binders before eating that grab excess phosphorus, found in high levels in animal protein and processed foods, so more will be eliminated from the gut and less absorbed into the blood. Dietitians help patients minimize phosphorus intake, and blood levels of phosphorus and calcium are regularly monitored, often as kidneys are failing and before dialysis has even begun.

However, physicians may need to be even more diligent and aggressive particularly in these high-risk populations, Huber said. This may include additional diet changes, taking more phosphorus binders, and more frequent dialysis. She notes that no prospective studies have measured the effectiveness of these current interventions.

A specific diagnostic code for calciphylaxis – currently, it shares one with multiple other conditions resulting from calcium-phosphorus abnormalities – could ease future studies of this relatively small population of patients, Huber said. This could include examining more detailed clinical information that is currently housed at countless dialysis centers across the country.

Diabetes and hypertension are major causes of kidney failure, although Huber notes that many kidney failure patients are not obese.

http://www.medicalnewstoday.com/releases/277707.php

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