Effect of Vitamin C on bleeding and pain after kidney biopsy: a randomized controlled trial

Percutaneous renal biopsy (PRB) is an essential diagnostic procedure for kidney diseases, yet postbiopsy perirenal hematoma and pain remain frequent complications. Vitamin C has emerging evidence supporting its role in reducing perioperative bleeding and pain, but its efficacy in the context of PRB is unknown.

This single-center, prospective, open-label, randomized controlled trial enrolled 710 adults with chronic kidney disease (CKD) scheduled for an ultrasound-guided native kidney biopsy. Participants were randomly assigned (1:1) to receive perioperative intravenous vitamin C (20 mg/kg at 6 h before and 18 h after biopsy) or standard care alone. The primary outcomes were the area of perirenal hematoma on renal ultrasound at 24 h and self-reported pain intensity (Visual Analogue Scale, VAS) at 2, 12, and 24 h post-biopsy.

All 710 randomized participants were included in the analysis. The adjusted mean difference in hematoma area at 24 h was 4.44 mm² (95% CI, -52.31 to 61.18; P = 0.878). After multiple testing correction, there were no significant differences in the primary pain outcome (VAS scores) between groups at any time point; however, an exploratory analysis of pain severity categories indicated a less favorable distribution in the Vitamin C group at 12 h (P for trend =0.033). The incidence of any perirenal hematoma was 56.3% in the vitamin C group versus 50.1% in the control group (risk ratio, 1.12; 95% CI, 0.98-1.29; P = 0.098). Rates of other bleeding complications and adverse events were low and comparable between groups.

In CKD patients undergoing PRB, perioperative intravenous vitamin C did not reduce the size of perirenal hematoma, alleviate postbiopsy pain, or decrease the incidence of bleeding complications within 24 h. These findings do not support the routine use of vitamin C for preventing complications after kidney biopsy.