Urinary microprotein concentrations in the long-term follow-up of dilating vesicoureteral reflux patients who underwent medical or surgical treatment

Purpose This study examined the relationship between urinary microprotein concentrations and renal functional parameters in children with dilating (grade III–V) vesicoureteral reflux (VUR) who underwent either medical or surgical treatment. Methods All 44 dilating VUR patients who were followed for 4 years were screened for inclusion in this study. The patients’ clinical features and clinical outcomes, as well as the urinary activities of albumin (ALB), transferrin (TRF), immunoglobulin G (IgG), alpha-1-microglobulin (α1-MG), and N -acetyl-β-glucosaminidase (NAG), were retrospectively analyzed. Results High values of NAG, α1-MG, IgG, TRF, and ALB were noted in 73.33, 58.33, 43.33, 24.14, and 53.33 % of patients, respectively, at the first examination. Cystatin C, eGFR, and urinary microprotein levels were associated with a good prognosis after 4 years of follow-up. No differences in recurrent UTI, cystatin C concentration, most microprotein/creatinine (Cr) ratios, eGFR, or ΔGFR4 % were found between the groups. High levels of urinary proteins were found in 2.38–9.52 % of cases after 4 years of follow-up. ALB/Cr, IgG/Cr, and α1-MG/Cr levels were positively correlated with 99mTc-dimercaptosuccinic acid (DMSA) grade, and α1-MG excretion was inversely correlated with eGFR. Conclusions The levels of microprotein were elevated at diagnosis in a higher proportion of patients than for the other markers examined. At long-term follow-up, the reflux level had decreased or completely resolved in all patients, and the proportions of microproteins that were elevated were significantly reduced. Renal impairment measured by eGFR and DMSA grade was related to increased urinary α1-MG levels.