AIM: To evaluate whether renal length z-scores predict renal dysfunction in children with a solitary functioning kidney (SFK).

METHODS: In a single-centre retrospective cohort of children with SFK, we correlated body mass index z-scores, extracellular volume and lean body mass to renal length z-scores. We grouped these z-scores to other markers of renal dysfunction (proteinuria, hypertension, extracellular volume and abnormal estimated glomerular function rate [eGFR]) and analysed renal length z-score with multivariate analysis, receiver-operated characteristics (ROC) plots and Youden's index to determine an appropriate cut-off.

RESULTS: 111 children had a median follow-up 5.08 years, eGFR 80.8 mL/min/1.73 m

CONCLUSION: In this cohort of children with SKF, using the renal length z-score as a biomarker of renal dysfunction at 7 years of age is not recommended.