Effect of Two Vitamin D Repletion Protocols on 24-hour Urine Calcium in Patients with Recurrent Calcium Kidney Stones and Vitamin D Deficiency: A Randomized Clinical Trial

Abstract

Abstract Objectives The effect of two treatment protocols on serum levels of vitamin D and 24-hour urine calcium in patients with calcium urolithiasis and vitamin D deficiency Design, Setting, Participants A parallel-group randomized controlled clinical trial on patients who referred to Labbafinejad stone prevention clinic, Tehran, Iran. From 88 recurrent calcium kidney stone formers, 62 patients completed the study. The age of study participants were 18 to 70 years old and, had serum 25-hydroxyvitamin D (25(OH)D) level 10–20 ng/ml. Intervention Study participants received 2000 IU vitamin D daily for 12 weeks or 50000 IU vitamin D weekly for eight weeks. Main outcome measures Study variables including 24-hour urine calcium, supersaturations of calcium oxalate and calcium phosphate, serum 25-hydroxyvitamin D and parathormone were measured at the beginning and after 12 weeks. Results The 24-hour urine calcium significantly increased in both groups (B = 69.70, p < 0.001), with no significant difference between treatments. Both groups showed no significant change in the supersaturation levels of calcium oxalate and calcium phosphate. Serum 25-hydroxyvitamin D increased significantly (B = 12.53, p < 0.001), with more increase in the 50,000 IU group (B = 3.46, p = 0.003). Serum parathormone decreased in both groups (p < 0.001). Conclusions Although both treatment protocols increased 24-hour urine calcium, they did not increase the supersaturation state of calcium oxalate or calcium phosphate. Trial registration IRCT20160206026406N4, 13/08/2019