Tetsuo Shoji, MD, PhD.
Department of Vascular Medicine
Osaka City University Graduate School of Medicine
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Vitamin D is known to be associated with health and disease of various organs such as bone, heart, brain, and others. Vitamin D is activated by the liver and kidneys to a hormone called 1,25-dihydroxyvitamin D which binds to vitamin D receptor in cells to exert its functions.
Vitamin D activation is severely impaired in patients with kidney disease requiring hemodialysis therapy, leading to mineral and bone disorder(MBD). Therefore, active form of vitamin D is one of the standard choices of treatment for MBD caused by kidney function loss.
Previous observational cohort studies showed that the use of active vitamin D in hemodialysis patients was associated with lower likelihood of all-cause death, cardiovascular death, and incident cardiovascular disease.Potentially cardio-protective effects of active vitamin D were shown by basic studies using cultured cells and animal models. Then, many nephrologists began to believe that active vitamin D is a “longevity hormone” or a “panacea” for kidney patients requiring dialysis therapy, although there was no evidence by randomized clinical trials.
To show evidence for it, we conducted a randomized clinical trial namedJ-DAVID in which 976 hemodialysis patients were randomly assigned to treatment with oral alfacalcidol or treatment without active vitamin D, and they were followed-up for new cardiovascular events during the four-year period. The risk of cardiovascular events was not significantly different between the two groups. The risk of all-cause death was not significantly different either.
To our surprise, the risk of cardiovascular event tended to be higher in the patients who continued treatment with active vitamin D than those who continued non-use of active vitamin D, although the difference was not statistically significant.