Urinary periostin as a novel non-invasive biomarker for kidney scarring in pediatric vesicoureteral reflux patients.

Background: Vesicoureteral reflux (VUR) is a common pediatric urological condition associated with kidney scarring, which can lead to hypertension, proteinuria, and chronic kidney disease. Current diagnostic methods, such as 99mTc-dimercaptosuccinic acid (DMSA) scans, are costly, involve radiation, and fail to detect early fibrosis. Urinary periostin, an extracellular matrix protein upregulated in kidney fibrosis, holds promise as a non-invasive biomarker for kidney scarring in VUR patients. This study aimed to evaluate urinary periostin as a biomarker for kidney scarring in children with VUR and compare its diagnostic performance with DMSA scans.

Methods: This prospective case-control study enrolled 60 children (35 males and 25 females) aged between 1 and 140 months (with mean (SD) of 43.7 (34.45)) with VUR (30 with kidney scarring [Scar+] and 30 without [Scar-]). Urinary periostin levels were measured via ELISA and corrected with urine creatinine. DMSA scans confirmed scarring. Receiver operating characteristic (ROC) analysis assessed periostin's diagnostic accuracy, and logistic regression identified predictors of scarring.

Results: Urinary periostin levels were significantly higher in Scar+ patients (27.4 ± 6.64 ng/mL) than in Scar- patients (18.1 ± 4.63 ng/mL, p < 0.001). ROC analysis yielded an area under the curve of 0.869, with a 21.5 ng/mL cutoff showing 80.0% sensitivity and 76.6% specificity. Periostin (OR 1.44, p < 0.001) was the only independent predictor of scarring. Periostin levels correlated with VUR grade (r = 0.63, p < 0.001).

Conclusions: Urinary periostin is a highly sensitive and specific non-invasive biomarker for detecting kidney scarring in VUR, potentially reducing reliance on DMSA scans.