Vitamin D and outcomes in chronic kidney disease

There is a high prevalence of vitamin D deficiency in the chronic kidney disease population. Vitamin D is often administered to patients to mitigate detrimental effects on bone health and mineral metabolism, though this treatment may be limited by elevations in serum calcium and phosphorus. This article reviews the basic physiology of vitamin D, the survival data in patients receiving vitamin D, and the current quandary of whether vitamin D administration is beneficial in chronic kidney disease.

Despite potential increases in serum calcium and phosphorus due to activation of vitamin D receptors in the gut, vitamin D administration has been associated with a survival benefit in recent studies. While the mechanism for this possible benefit is unknown, vitamin D administration may have effects beyond its traditional role in mineral metabolism, mediated through the activation of vitamin D receptors distributed in a variety of tissues.

Data currently suggests that the administration of vitamin D confers a survival benefit to patients on dialysis. There is no clear mechanism, however, to explain this association. Further research is needed to clarify the expanding role of vitamin D receptor activation, particularly in vascular calcification, and the effects of the different forms of vitamin D.