Kidney injury and congenital solitary functioning kidney: more research efforts are needed

We appreciated the study by Groen in 't Woud et al., investigating for risk factors of kidney injury (KI) in a large cohort of solitary functioning kidney. 1 Groen in 't Woud S. Roeleveld N. Westland R. et al. Uncovering risk factors for kidney injury in children with a solitary functioning kidney. Kidney Int. 2023; 103: 156-165 Abstract Full Text Full Text PDF Scopus (4) Google Scholar In this article, the prevalence of any KI was of 75% at 18 years of age in patients with congenital solitary functioning kidney (CSFK). It was significantly higher than the KI prevalence of 26.8% in a smaller population with similar age at last follow-up but with early-in-life enrollment. 2 Marzuillo P. Guarino S. Di Sessa A. et al. Congenital solitary kidney from birth to adulthood. J Urol. 2021; 205: 1466-1475 Crossref PubMed Scopus (15) Google Scholar Moreover, a higher percentage of congenital anomalies of the kidney and urinary tract in CSFK—which are strictly associated to KI—was found (46%) 1 Groen in 't Woud S. Roeleveld N. Westland R. et al. Uncovering risk factors for kidney injury in children with a solitary functioning kidney. Kidney Int. 2023; 103: 156-165 Abstract Full Text Full Text PDF Scopus (4) Google Scholar compared with the 20% to 26% prevalence in other cohorts enrolling patients with CSFK at a younger age. 2 Marzuillo P. Guarino S. Di Sessa A. et al. Congenital solitary kidney from birth to adulthood. J Urol. 2021; 205: 1466-1475 Crossref PubMed Scopus (15) Google Scholar , 3 La Scola C. Ammenti A. Puccio G. et al. Congenital solitary kidney in children: size matters. J Urol. 2016; 196: 1250-1256 Crossref PubMed Scopus (31) Google Scholar , 4 Poggiali I.V. Simões e Silva A.C. Vasconcelos M.A. et al. A clinical predictive model of renal injury in children with congenital solitary functioning kidney. Pediatr Nephrol. 2019; 34: 465-474 Crossref PubMed Scopus (25) Google Scholar This could ensue a partial oversampling of the severely affected patients. The authors replyKidney InternationalVol. 103Issue 2PreviewIn the last decades, several studies showed that congenital solitary functioning kidney (CSFK) predisposes to kidney injury, which was confirmed in our recent article in Kidney International.1 As Marzuillo et al. point out in their letter, the percentage of kidney injury found varies greatly between cohorts and is dependent on the prevalence of several risk factors, including congenital anomalies of the kidney and urinary tract in the CSFK.2 The relatively high number of patients with congenital anomalies of the kidney and urinary tract in the CSFK in our study could indicate some selection toward more severely affected patients. Full-Text PDF Uncovering risk factors for kidney injury in children with a solitary functioning kidneyKidney InternationalVol. 103Issue 1PreviewChildren with a solitary functioning kidney (SFK) have an increased risk of kidney injury. The exact risk of and risk factors for kidney injury remain unknown, which impedes personalized care. Here, we recruited a nationwide multicenter cohort of 944 patients with SFK to get more insight into this by consenting patients born in 1993-2020 and diagnosed with congenital or acquired SFK before adulthood. The median follow-up was 12.8 years and four indications of kidney injury were studied: urine protein-creatinine ratios, blood pressure, estimated glomerular filtration rate and use of anti-hypertensive/proteinuric medication. Full-Text PDF Open Access