Vitamin A supplementation is effective for improving the clinical symptoms of urinary tract infections and reducing renal scarring in girls with acute pyelonephritis: a randomized, double-blind placebo-controlled, clinical trial study

Abstract

Introduction: It is believed that tubulointerstitial inflammation plays a role in the formation of renal scarring secondary to acute pyelonephritis (APN). Vitamin A is an anti-inflammatory agent that is involved in the re-epithelialization of damaged mucosal surfaces.

Objective: The aim of this study was to evaluate the efficacy of vitamin A supplementation in combination with antibiotics for improving urinary tract infections (UTIs) symptoms and preventing renal scarring in girls with APN.

Study design: This randomized, double-blind, placebo-controlled clinical trial was conducted on 90 girls aged 2 to 12 years old between 2015 and 2017. Patients with UTIs and first episode of APN diagnosed based on 99 mTc-DMSA scintigraphy (uptake defect) were assessed for eligibility. Patients were randomly divided into two groups that either received 10 days of oral vitamin A (intervention group) or 10 days of placebo (control group) in addition to antibiotics during the acute phase of infection. The clinical response was considered as the primary outcome [duration (positive days) of UTI symptoms during trial treatment period] and secondary outcomes (no change, improving and or worsening of 99 mTc-DMSA scan results 6 months after treatment from baseline). P < 0.05 was considered to be statistically significant.

Results: Seventy-four patients (vitamin A group: 36 patients, placebo: 38 patients) were included in the analysis. The mean age was 5.25 ± 1 year old. Three patients (7.89%) in the placebo group and 2 patients (5.55%) in the vitamin A group had vesicoureteral reflux (VUR) (p = 0.114). Duration of fever (vitamin A group: 1.8 days, placebo: 3.1 days, p = 0.0026), urinary frequency (1.3 days vs. 2.8 days, p = 0.003) and poor feeding (2.3 days vs. 4.2 days, p = 0.005) were significantly lower in the vitamin A group. Following the second 99 mTc-DMSA scan, worsening of lesions was observed among 8 (22.2%) and 17 (44.7%) patients in the vitamin A and placebo groups, respectively (p = 0.003). 63.8% (23 patients) of the vitamin A group and 21% (8 patients) of placebo group showed lesion improving in the photopenic region. (P < 0.0001) There was no evidence of vitamin A intolerance.

Discussion: Our results show the efficacy of vitamin A supplementation on reducing renal scarring secondary to APN and on fever, urinary frequency and poor feeding duration in girls with APN.

Conclusion: Vitamin A supplementation is effective for improving the clinical symptoms of UTI and reducing renal injury and scarring following APN in girls with first APN. However, larger randomized clinical trials (RCTs) with longer follow up are needed to confirm these effects.

Keywords: 99mTc-DMSA; Pyelonephritis; Renal scar; Urinary tract infection; Vitamin A.