Background: Renal scarring after acute pyelonephritis (APN) in children is of concern and in the worst cases leads to long-term cardiovascular morbidity. There are reports that vitamin A may alleviate renal damage following APN. We conducted a meta-analysis to investigate the role of vitamin A in the alleviation of renal damage.

Methods: We searched PubMed, EMBASE, the Cochrane Central Register of Controlled trials (CENTRAL, the Cochrane Library) and the Wang Fang database (Chinese) from their inception to February 3, 2015 for randomized controlled trials (RCTs) investigating vitamin A and renal damage. Primary outcome was number of patients/kidneys with renal damage, defined as persistence of photopenic lesions based on technetium-99m dimercaptosuccinic acid renal scintigraphy. We calculated pooled relative risks for renal damage in the vitamin A group.

Results: Four RCTs, involving a total of 248 patients aged 1-144 months (120 in experimental group, 128 in control group), were included in the meta-analysis. Vitamin A was inversely associated with renal damage (relative risk 0.53, 95 % confidence interval 0.43, 0.67) when compared with placebo group after an average follow-up of 5 months.

Conclusions: Current evidence indicates that vitamin A may exert a preventive effect on renal damage in children with APN. However, this finding largely relies on a few studies of low methodological quality, i.e., high risk of selection bias, performance bias and attrition bias. Hence, high-quality and adequately powered RCTs are warranted.