Vitamin D supplementation linked with reduced proteinuria in patients with CKD
Supplementary vitamin D in low doses may reduce proteinuria in patients with chronic kidney disease, according to results of a nonblinded, non-placebo-controlled study.
The 24-week study included 60 patients with CKD who received a stable dose of either angiotensin receptor blocker (ARB) or angiotensin-converting enzyme inhibitor (ACEI) for more than 1 month. Patients had an average estimated glomerular filtration rate of more than 15 mL/min. Researchers assigned these patients into either a vitamin D group or a control group. The primary endpoint of the study was to find a definitive percentage of urine protein/creatinine ratio (uPCR) change in patients with CKD.
“[T]he severity of proteinuria was found to decrease after calcitriol treatment in patients with CKD who received doses of an [renin-angiotensin-aldosterone system] RAAS inhibitor,” Chia-Chao Wu, PhD, of the department of internal medicine at Tri-Service General Hospital in the National Defense Medical Center in TaiPei, Taiwan, and colleagues, wrote.
Researchers found the uPCR in the vitamin D group decreased significantly at 8 and 16 weeks, with a result of 2.02 ± 0.25 g/g to 1.35 ± 0.17 g/g at the end of the 24 weeks. A positive correlation was found between reduction in uPCR in the vitamin D group at 24 weeks and baseline serum 25-(OH) D levels.
According to the researchers, findings from the study were consistent with results of other studies that showed vitamin D therapy exerts similar antiproteinuric effects in patients with CKD treated with a RAAS inhibitor.
“In conclusion, supplementary low-dose active vitamin D could significantly reduce the severity of proteinuria among patients with CKD,” the researchers wrote. They added, “Therefore, we suggest that prospective long-term and larger studies should be conducted to determine whether earlier commencement of vitamin D therapy in patients with CKD would be beneficial and whether the therapy can delay CKD progression.” –by Erin T. Welsh