PHILADELPHIA—Move over EPO, vitamin D is the next renal drug class to be questioned by medical pundits and policy makers.
A new study in the Dec. 18, 2007, issue of the Annals of Internal Medicine called into question the actual scientific benefits of vitamin D compounds often prescribed to chronic kidney disease patients. CKD patients often have weakened bones due to a lack of vitamin D, which helps regulate calcium and phosphorus levels as well as with calcium absorption.
"Vitamin D compounds do not consistently reduce PTH levels, and beneficial side effects on patient-level outcomes are unproven," the authors concluded. "The value of vitamin D treatment with chronic kidney disease remains uncertain."
The researchers set out to determine if vitamin D therapy helped alleviate the risk of cardiovascular events, bone fractures and death. They performed a meta-analysis of 76 clinical trials that occurred between 1966 and 2007 that studied a total of 3,667 patients.
They chose randomized, controlled trials of vitamin D use in CKD patients and found that vitamin D therapy did not reduce the risk of death, bone pain, vascular calcification or reduce parathyroid hormone levels, which become too active and remove too much calcium in the bones.
The meta-analysis was limited by the studies it covered, and the researchers called for more research into the therapy’s effectiveness. "Palmer and colleagues’ finding should serve as yet another warning to the nephrology community that we do not have good evidence to defend many of our common practices," Marcello Tonelli, MD, associate professor of medicine, University of Alberta, wrote in an editorial accompanying the study.
In an interview with WebMD, Tonelli suggested that large-scale trials are needed to study vitamin D therapy in CKD patients, and that perhaps these studies should be funded by large U.S. agencies such as the National Institutes of Health.
