Comparison of the effects of valsartan plus activated vitamin D versus valsartan alone in IgA nephropathy with moderate proteinuria

Background/aims To compare the effects of valsartan plus activated vitamin D with valsartan alone on urinary protein excretion and eGFR in IgA nephropathy with moderate proteinuria. Methods A prospective, single-center, randomized, controlled study was performed between Jan, 2008 and Jan, 2018 on patients with IgA nephropathy who had moderate proteinuria with urinary protein excretion 1.0-3.0 g/24 h. These IgAN patients were randomly assigned to receive either valsartan 160 mg/day treatment or valsartan 160 mg/day plus activated vitamin D (calcitriol) 0.5 mu g/day treatments. The changes of the clinical, biochemical data, and the adverse events during the observation period were all analyzed in the two groups. The primary endpoint was defined as changes in urinary protein excretion at week 24 compared with the baseline and the secondary endpoint was to observe the changes in estimated glomerular filtration rate (eGFR) between baseline and the end of the study. Results Baseline characteristics between the two groups were comparable. At the end of the treatment period, urinary protein excretion in both two groups decreased significantly (P < 0.05). However, there was a more significant decrease in proteinuria in IgAN patients who received valsartan plus activated vitamin D treatment (from 2.39 +/- 0.77 to 1.43 +/- 0.57 g/24 h, P < 0.01) compared to valsartan treatment alone (from 2.46 +/- 0.81 to 1.78 +/- 0.60 g/24 h, P < 0.05). The percentage change in urine protein excretion at week 24 was - 40.2% in valsartan plus activated vitamin D treatment group (P < 0.01) and - 27.6% in valsartan treatment group (P < 0.05). No significant change in blood pressure, estimated glomerular filtration rate, serum calcium, and serum potassium was observed. The incidence of adverse events was similar between the two groups, respectively (P > 0.05). Conclusion Combination therapy with valsartan plus activated vitamin D is more effective than valsartan alone in reduction of moderate proteinuria in IgA nephropathy and without more adverse events.