S KEENAN1, N HOMAIRA1, S KENNEDY1,2
1School of Women’s & Children’s Health, University Of New South Wales, Sydney, Australia, 2Sydney Children’s Hospital , Randwick, Australia
Aims: To identify patient-related factors which predict low glomerular filtration rate (GFR) in boys with posterior urethral valves (PUV).
Background: PUV are a congenital anomaly and an important cause of chronic kidney disease (CKD) in childhood. Up to 40% of boys who are born with PUV will develop end-stage kidney disease (ESKD) by early adulthood. Accurate prognostication of renal outcome is important to counsel families and guide treatment.
Methods: A single-centre cohort study of boys born with PUV between 1999 and 2017. Primary outcomes of interest were renal replacement therapy (RRT) or CKD stage 3-5. Perinatal and clinical variables were analysed using univariate and multivariate Cox models. Prognostic indicators were validated using ROC and survival analysis.
Results: A cohort of 60 boys was identified with median follow up of 61 months (range 6-210 months). Seven (12%) and 20 (33%) boys progressed to RRT and CKD3-5, respectively. On univariate analysis, nadir serum creatinine (SCr) in the first year of life, eGFR at 12 months of age and oligohydramnios were predictors of outcome. Only nadir SCr was predictive of RRT/CKD3-5 on multivariate Cox regression (HR 1.020, 95% CI 1.01-1.03; p<0.01). CKD- and RRT-free survival were significantly predicted by stratifying nadir SCr in to 3 categories: low, < 35μmol/L (<1% developed CKD3-5), moderate, 35-75μmol/L (55% developed RRT/CKD3-5) and high, >75μmol/L (100% developed RRT/CKD3-5). Kaplan-Meier plots showed different event-free survival times between each of the three stratifications of nadir SCr (p<0.001).
Conclusions: Our study confirms the predictive value of nadir SCr, and increased sensitivity of a lower cut-off of 35 μmol/L. This knowledge will assist with prognostication and allows identification of boys who may be suitable for intervention trials.
Sarah is a 5th year medical student at the university of New South Wales. This research was conducted as part of B Med Sc (Honours) studies in 2017.