The prevalence of vitamin D deficiency in pre-dialysis patients with chronic kidney disease

Introduction: Reduced vitamin D levels were seen early in the course of chronic kidney disease (CKD). Its prevalence increased and severity worsened with the progression of CKD.

Aim: To assess the prevalence of vitamin D deficiency in pre-dialysis CKD patients.

Material and methods: In the study 100 adult patients were divided into three groups depending on estimated glomerular filtration rate (eGFR). Group A consisted of 30 patients with eGFR between 30–49 ml/min, group B consisted of 33 patients with eGFR between 15–29 ml/min, and group C had 37 patients with eGFR less than 15 ml/min. Renal functions, intact parathyroid hormone, 25 hydroxy vitamin D, and 1,25 dihydroxy vitamin D were measured at baseline.

Results: The mean serum phosphate and iPTH levels increased steadily as CKD progressed. On the other hand, mean corrected serum calcium levels, 25 hydroxy vitamin D, and 1,25 dihydroxy vitamin D decreased progressively in group A, B, and C. There was a significant increase in mean serum iPTH level from group A to group C (p < 0.05). The mean level of 25 hydroxy vitamin D and 1,25 dihydroxy vitamin D showed a trend of declination from group A to C (p < 0.05). Both 25 hydroxy vitamin D and 1,25 dihydroxy vitamin D positively correlated with eGFR. There was negative correlation of 25 hydroxy vitamin D and 1,25 dihydroxy vitamin D with iPTH and proteinuria.

Conclusions: The study concluded that both prevalence and severity of low 25 hydroxy and 1,25 dihydroxy vitamin D increases with progression of CKD. Their levels were negatively correlated to factors like parathyroid hormone levels and proteinuria.