Olivia Boyer1,2, Frank Bienaimé3,4, Mathilde Grapin1,5,6, François Gaillard7, Nathalie Biebuyck1, Melissa Ould-Rabah8, Carole Hennequin9, Romain Berthaud1,2, Guillaume Dorval1,2, Thomas Blanc5,10, Maryvonne Hourmant11, Nassim Kamar12, Lionel Rostaing13, Lionel Couzi14, Nicolas Garcelon2, Dominique Prié5,8. 1. Service de Néphrologie Pédiatrique, Centre de référence Marhea, Hôpital Necker-Enfants malades, Assistance Publique-Hôpitaux de Paris, Paris, France. 2. Institut Imagine, Inserm U1163, Université de Paris, Paris, France. 3. Université de Paris, Institut Necker-Enfants Malades Inserm U1151, Paris, France. frank.bienaime@inserm.fr. 4. Service de Physiologie, Hôpital Necker-Enfants malades, Assistance Publique-Hôpitaux de Paris, Paris, France. frank.bienaime@inserm.fr. 5. Université de Paris, Institut Necker-Enfants Malades Inserm U1151, Paris, France. 6. Sorbonne Université, Paris, France. 7. Service de Néphrologie, Hôpital Bichat, Assistance Publique-Hôpitaux de Paris, Paris, France. 8. Service de Physiologie, Hôpital Necker-Enfants malades, Assistance Publique-Hôpitaux de Paris, Paris, France. 9. Service de Biochimie, Hôpital Necker-Enfants malades, Assistance Publique-Hôpitaux de Paris, Paris, France. 10. Service de Chirurgie Pédiatrie, Hôpital Necker-Enfants malades, Assistance Publique-Hôpitaux de Paris, Paris, France. 11. Service de Transplantation Rénale, CHU Nantes, Nantes, France. 12. Service de Néphrologie et de Transplantation, CHU Rangueil, Toulouse, France. 13. Service de Néphrologie, Hémodialyse, Aphérèses et Transplantation, Centre Hospitalier Universitaire Grenoble-Alpes, Grenoble, France. 14. Service de Néphrologie, Transplantation, Dialyse et Aphérèse, CHU de Bordeaux, Bordeaux, France.
Abstract
BACKGROUND: A precise assessment of glomerular filtration rate is key to delineate the care of children with a solitary functioning kidney (SFK). Data regarding measured GFR (mGFR) in this population is restricted to a single study of 77 individuals, which suggested that a GFR estimation (eGFR) method based on creatinine and cystatin C (eGFR-CKiD2) performed better than Schwartz's equation (eGFR-Schwartz). METHODS: We measured GFR in 210 consecutive adolescents (7 to 22 years old) with an SFK referred to our institution between 2014 and 2019 and in 43 young candidates for kidney donation (18 to 25 years old). We compared the distribution of mGFR in both groups and determined the factors associated with reduced mGFR in adolescents with an SFK. We further compared different eGFR formulas with mGFR and assessed the association of mGFR and eGFRs with PTH and FGF23, two early indicators of GFR reduction. RESULTS: While adolescents with an SFK had a similar median mGFR to healthy controls (103 ± 24ml/min/1.73m2 vs. 107 ± 12 ml/min/1.73m2), the fraction of individuals with an mGFR below 90 ml/min/1.73m2 was higher in patients with SFK (23% vs. 5% in controls; P = 0.005). Multiple linear regression identified older age, ipsilateral abnormalities of the urinary tract, lack of compensatory hypertrophy, and treated hypertension as independent factors associated with reduced mGFR. A smaller bias using eGFR-Schwartz (95% confidence interval (95%CI): 3 to 7) was revealed when compared to other eGFR. Compared to eGFR-Schwartz, mGFR showed a stronger correlation with PTH (r = 0.04 vs. r = 0.1) and FGF23 (r = 0.03 vs. r = 0.05). CONCLUSION: SFK is not a benign condition, since 20% of the patients display altered kidney function. Our results raise caution regarding the use of the cystatin-based equation. mGFR shows a better ability than eGFR-Schwartz to differentiate patients showing early homeostatic adaptation to GFR reduction.
BACKGROUND: A precise assessment of glomerular filtration rate is key to delineate the care of children with a solitary functioning kidney (SFK). Data regarding measured GFR (mGFR) in this population is restricted to a single study of 77 individuals, which suggested that a GFR estimation (eGFR) method based on creatinine and cystatin C (eGFR-CKiD2) performed better than Schwartz's equation (eGFR-Schwartz). METHODS: We measured GFR in 210 consecutive adolescents (7 to 22 years old) with an SFK referred to our institution between 2014 and 2019 and in 43 young candidates for kidney donation (18 to 25 years old). We compared the distribution of mGFR in both groups and determined the factors associated with reduced mGFR in adolescents with an SFK. We further compared different eGFR formulas with mGFR and assessed the association of mGFR and eGFRs with PTH and FGF23, two early indicators of GFR reduction. RESULTS: While adolescents with an SFK had a similar median mGFR to healthy controls (103 ± 24ml/min/1.73m2 vs. 107 ± 12 ml/min/1.73m2), the fraction of individuals with an mGFR below 90 ml/min/1.73m2 was higher in patients with SFK (23% vs. 5% in controls; P = 0.005). Multiple linear regression identified older age, ipsilateral abnormalities of the urinary tract, lack of compensatory hypertrophy, and treated hypertension as independent factors associated with reduced mGFR. A smaller bias using eGFR-Schwartz (95% confidence interval (95%CI): 3 to 7) was revealed when compared to other eGFR. Compared to eGFR-Schwartz, mGFR showed a stronger correlation with PTH (r = 0.04 vs. r = 0.1) and FGF23 (r = 0.03 vs. r = 0.05). CONCLUSION: SFK is not a benign condition, since 20% of the patients display altered kidney function. Our results raise caution regarding the use of the cystatin-based equation. mGFR shows a better ability than eGFR-Schwartz to differentiate patients showing early homeostatic adaptation to GFR reduction.
Authors: Derek K Ng; George J Schwartz; Michael F Schneider; Susan L Furth; Bradley A Warady Journal: Kidney Int Date: 2018-05-05 Impact factor: 10.612