The Role of Urinary Biomarker Levels in Assessing the Presence and Severity of Ureteropelvic Junction Obstruction in Children: A Systematic Review and Meta-Analysis

Context Ureteropelvic junction obstruction (UPJO) is the most common obstructive disease of the urinary tract in infancy and childhood with a prevalence of 15% - 45% in neonates with antenatal hydronephrosis. The diagnosis of UPJO should be confirmed by imaging studies - most of which have a propensity to radiation exposure. Objectives The current study aimed to present a review protocol to assess the role of measuring urinary biomarkers to distinguish severe UPJO from milder forms of the disease. Data Sources The database of UPJO studies was searched and studies that compared the levels of urinary biomarkers with the gold standard (i e, dynamic renal scans) for UPJO diagnosis were selected. Severity assessment was done quantitatively. Study Selection Three hundred fifty-eight articles were identified across the electronic databases. Twenty-seven articles were selected for the final analyses. Data Extraction Data were extracted independently by three reviewers and analyzed using STATA software version 12. Results Meta-analysis of studies showed that patients with severe UPJO had significantly higher biomarker levels than those with mild to moderate obstruction, with a pooled standardized mean difference (SMD) of 0.5 (confidence interval (CI) 95%, 0.34 - 0.67; P < 0.001); and significantly higher biomarker standardized to urinary creatinine levels than those with mild to moderate obstruction, with a pooled SMD of 1.02 (95% CI, 0.88 - 1.16; P < 0.001). Meta-analysis showed that patients with severe UPJO had significantly higher biomarker levels than healthy children, with a pooled SMD of 1.27 (CI 95%, 1.16 - 1.39; P < 0.001); and significantly higher biomarker standardized to urinary creatinine levels than healthy children, with a pooled SMD of 1.14 (CI 95%, 0.95 - 1.32; P < 0.001). Conclusions The assessment of urinary biomarkers is a helpful tool to assess the presence and severity of UPJO, but there is little published data on each of the studied biomarkers. It is suggested to perform future larger multicenter studies.