The role of vitamin D levels in the development and progression of kidney disease: The current state of the problem. A review

Progressive loss of kidney function is associated with significant morbidity and mortality and is an important global health concern, given the high prevalence of chronic kidney disease (CKD). Recently, there has been an increased interest in finding new therapeutic strategies that may slow the progression of renal dysfunction. Numerous studies using various experimental models have proven that treatment with active metabolites of vitamin D can have a renoprotective effect, preventing fibrosis, apoptosis, and inflammation. In addition, vitamin D deficiency and insufficiency are common conditions in CKD patients in the pre-dialysis stages. It has been established that the vitamin D serum level is directly proportional to kidney function. Recent clinical studies have shown that reducing proteinuria and mortality in CKD patients receiving active vitamin D goes beyond the classical role of vitamin D in maintaining bone and mineral metabolism. Therefore, vitamin D analogs have the potential to become components of CKD treatment to achieve better clinical outcomes in patients with advanced kidney disease and those on hemodialysis. Current guidelines recommend treatment with vitamin D only in patients with moderate CKD with secondary hyperparathyroidism and vitamin D deficiency. This review presents the results of numerous studies demonstrating the prevalence of vitamin D deficiency among patients with various kidney diseases, the effect of vitamin D in reducing the rate of CKD progression, as well as the clinical outcomes of vitamin D use in patients with infectious and non-infectious kidney diseases.