Does severity of renal scarring on DMSA scan predict abnormalities in creatinine clearance?

To examine the relationship between severity of renal scarring and creatinine clearance. Existing studies on renal scarring and functional outcomes have focused on the presence or absence of scarring.

Patients with a history of urinary tract infection leading to the diagnosis of vesicoureteral reflux were recruited. These subjects were admitted to a pediatric research center for an in-patient collection of 24-hour urine to be sent for creatinine and protein. DMSA scans performed at least 6 months after documented urinary tract infection were graded by 3 independent, blinded pediatric urologists for renal scarring according to the Randomized Intervention for Children with Vesicoureteral Reflux study criteria.

Twenty-nine subjects (14 girls, 15 boys) with a median age of 7 years were recruited. Scar grading was reliable between the observers with a Kappa score of 0.66-0.75. On DMSA scan, 10% were scar-free, 62% had unilateral scars, and 28% had bilateral scars. Mean creatinine clearance was 123 for those with unilateral disease and 100 for those with bilateral disease (P = .048). Median proteinuria (58 mg/dL) and serum creatinine (0.5 mg/dL) were similar between the 2 groups. Creatinine clearance did not differ according to average scar grade, taking both kidneys into account.

In children with vesicoureteral reflux, although those with bilateral scarring have a significantly lower creatinine clearance than those with unilateral scarring, the severity of scar grade alone does not predict overall creatinine clearance with short-term follow-up.