Vesicoureteral reflux (VUR) is one of the most common anomalies of the urinary system that predisposes to recurrent pyelonephritis, hypertension, renal parenchymal scars, and chronic renal failure if not managed properly. Recent studies show that microalbuminuria is a marker of glomerular damage at early stages. In adults, microalbuminuria is considered a risk factor for the occurrence of nephropathy. However, the data are limited in children.
The goal of this study was to evaluate the relationship between microalbuminuria and kidney scarring, creatinine clearance, and severity of reflux in children with VUR.
In this cross-sectional study, 87 children aged <14 years with VUR referred to Children's Hospital of Tabriz, Iran, were studied from 2012 to 2013. VUR was detected by using radiologic voiding cystourethrography. Urine microalbumin measurements and renal 99mTc-dimercaptosuccinic acid (DMSA) scans (for detecting scars) were performed in all patients 3 months after treatment of urinary tract infections. Creatinine clearance was calculated according to the Schwartz formula by using serum creatinine and patient height. Microalbuminuria was defined as 30 to 300 mg of microalbumin in 24-hour urine or a microalbumin to creatinine ratio of 0.03 to 0.3 in random urine. The relationship between variables was assessed by using SPSS software.
The mean age of the patients was 4.49 ± 2.64 years, and 82.8% of patients were female. Severity of reflux was mild (grades 1–2) in 23%, moderate (grade 3) in 33.3%, and severe (grades 4–5) in 43.7% of patients. Results of the DMSA scan were abnormal in 58 patients (66.6%). Microalbuminuria was detected in 19 patients (21.8%), and the amount of microalbumin was in the normal range in 68 patients (78.2%). With increasing grading of reflux, the amount of microalbuminuria increased and the amount of creatinine clearance decreased, but the changes were not statistically significant (P > .05). Urinary microalbumin in patients with scarred kidneys (33.32 ± 28.69 mg) was significantly higher than in patients without scarring (10.82 ± 8.83 mg) (P = .006). The frequency of scarred kidneys in mild, moderate, and severe grades of reflux was 50%, 62.1%, and 78.9%, respectively (P = .07). Frequency of microalbuminuria was 31% in patients with scarring, and only 3.4% of patients without scarring had microalbuminuria (P = .003). There was no significant difference in frequency of microalbuminuria and kidney scarring between boys and girls (P > .05).
In this study, we found no significant correlation between microalbuminuria, creatinine clearance, and abnormality on DMSA scans with grading of reflux. However, there was a significant correlation between microalbuminuria and presence of scars in the kidney. Microalbuminuria may be considered a marker for renal parenchymal damage.
- Copyright © 2015 by the American Academy of Pediatrics