TOPIC DISCUSSION: 25-OH Vitamin D and ESRD

The KDOQI has now started recommending that we check inactivated Vitamin D levels in all CKD patients with hyperparathyrodism and if the level is <30, to start replacing them with either D2 50,000 units once a week for 3 months or D3 1000 units once a day for 3 months.  This is the nutritional deficiency recommendation based on the general population. There have been many studies in the general population with effects on even none bone/muscle organs: cancer prevention, decreased renin, decreased cardiac disease and so forth.

1. What are the implications of this in CKD and ESRD population?
2. Does it matter to replace inactivated vitamin D in ESRD patients?
3. Won't the inactivated D be more suppressed in our ESRD patients since we are giving them activated Vitamin D, sometimes in excess?
A recent study showed that lower levels of the inactivated Vitamin D was associated with increased mortality in HD patients but the administration of activated vitamin D to these patients decreased the mortality.
There is one study by Bert et al, that found that vitamin D3 was not as effective as activated vitamin D in decreasing pth levels in dialysis patients.   Bone biopsies actually showed worsening of disease.
There is 1 alpha hydroxylation happening else where, mainly macrophages and other cells besides the kidney. Giving 25-OH might activated those cells to convert more and we can get extra renal activations.  
But again, data is observational and there is no harm in giving nutritional supplemental vitamin D as long as the calcium and phosphorus are in good range.
The role of a combination of a calcimimetic and 25-0h vitamin D might be interesting to look at according to many experts.  Well designed trials comparing both measures of just vitamin D alone vs vitamin D + calcimimetic vs activated vitamin D alone might be worth looking at.


Look at the below references
The first one is a nice review on all bone diseases in CKD( a nice table is in the article that summarizes a lot), good board prep table.
Kalantar-Zadeh K, Shah A, Duong U, Hechter RC, Dukkipati R, Kovesdy CP. Kidney Bone Disease and Mortality in CKD: Revisiting the role of Vitamin D, calcimimetics, alkaline phosphatase, and minerals. Kidney Int 2010:78 (suppl 117):S10-S21.
http://www.ncbi.nlm.nih.gov/pubmed/17687259
http://www.ncbi.nlm.nih.gov/pubmed/208439