Serum Urate Lowering Therapy Using Allopurinol Improves Serum 25 Hydroxy Vitamin D in Stage 3-5 CKD Patients: A Pilot...

Recent studies have demonstrated negative associations of serum uric acid (SUA) with serum 25 hydroxy vitamin D (25 [OH] vit D) among CKD patients.

The aim of the study was to look for the impact of hypouricemic therapy using allopurinol on serum level of 25 (OH) vit D in CKD patients.

Seventy-two CKD stage 3-5 patients were selected to this study. Patients with SUA above 7 mg/dL were allocated to hypouricemic therapy using allopurinol (group I). A control group of cases not suffering marked increase in SUA were included as control group (group II). All cases were followed up for 3 months. Serum Cr, SUA, ionized calcium (SiCa), phosphorus, 25 (OH) vitD, parathyroid hormone (PTH), and 24-h urine protein were estimated at entry and by the end of the study.

At least 20 cases completed the study in each group. Serum 25 (OH) vit D significantly increased in group I (26.4 [14.1] vs. 39.6 [14.8] at entry vs. at end of the study, p < 0.001). In addition, SUA, PTH, and urine protein significantly decreased (11 [1.6] vs. 3.95 [0.58] mg/dL, 267.5 [97.5] vs. 225.5 [153] ng/mL, and 2.7 [1.18] vs. 1.5 [1.08] gm/day, p < 0.001, = 0.043, and <0.001 respectively). SiCa and phosphorus significantly increased (4.4 [0.3] vs. 5.2 [0.5] mg/dL and 4.25 [0.72] vs. 4.9 [0.75] mg/dL, p < 0.001 and = 0.007, respectively).

This study supports a negative causal relationship between SUA and serum 25 (OH) vit D. Further studies are still needed to confirm this conclusion.