The original CKD-EPI and MDRD studies showed an association between African-American race with higher measured GFR at the same blood creatinine concentration. However, there have been concerns raised about the application of the race multiplier to all African-American patients. First, there is no clear biological explanation for the association, the identification of Black race was unclear in some of the cohorts used in these studies, and there is vast genetic and ancestral heterogeneity among those who self-identify as black. The use of the race multiplier also ignores the fact that race is a social, not biological construct.
We found that with the removal of the race multiplier, up to one in every three African-American patients would be reclassified as having a more severe stage of CKD, with one-quarter of African-American patients going from stage 3 to stage 4. We also found that with the removal of the race multiplier, 64 patients would have had an eGFR <20, the threshold for referral for kidney transplant, and none of these patients were referred, evaluated or waitlisted for transplant. This is in contrast, to those African-American patients with an eGFR <20 with the race multiplier applied, who had a higher odds of being referred, evaluated or waitlisted for transplant compared to other racial groups (Odds ratio of 2.28, compared to White cohort).(more…)
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.