ESPN 53rd Annual Meeting

ESPN 2021


 
Assessment of glomerular and tubular function in the evaluation of children with Sickle Cell Disease
EDOUARD ROLLOT 1 IONA MADDEN 2 JUSTINE BACCHETTA 1 LAURENCE DUBOURG 3

1- CENTRE DE RéFéRENCE DES MALADIES RéNALES RARES, SERVICE DE NéPHROLOGIE PéDIATRIQUE, HôPITAL FEMME MèRE ENFANT, HOSPICES CIVILS DE LYON, BRON, FRANCE
2- CENTRE DE RéFéRENCE DES MALADIES RéNALES RARES, UNITé DE NéPHROLOGIE PéDIATRIQUE, CHU DE BORDEAUX, BORDEAUX, FRANCE
3- DéPARTEMENT DE NéPHROLOGIE, SERVICE DEXPLORATION FONCTIONNELLE RéNALE, HôPITAL EDOUARD HERRIOT, HOSPICES CIVILS DE LYON, LYON, FRANCE
 
Abstract:

Objectives: Renal tubular dysfunction in children with Sickle Cell Disease (SCD) is one of the earliest manifestations of the disease, but there is a lack of data. Sickle Cell Nephropathy (SCN) is defined by hyperfiltration followed by microalbuminuria. Our aim was to compare tubular function between SCD patients with and without glomerular involvement. Methods: This was a retrospective, single-center, cross-sectional study of all children with SCD admitted for comprehensive renal functional assessment at Lyon University Hospital, France, over a period of 18 years (1991-2009). Glomerular and tubular dysfunction was ascertained by collecting the following data: the measured glomerular filtration rate (mGFR) by inulin clearance, albuminuria, urine osmolality, reabsorption rates of chloride, sodium, potassium, calcium and magnesium as well as the tubular maximum re-absorption of phosphorus per unit volume of GFR (TmP/GFR). Results: Eighty-six children were included, aged from 2 to 20 years old (mean age of 10.6 years, 53% girls). Thirty-six children (42%) presented SCN including 22 (26%) with hyperfiltration (median mGFR 177 ml/min/1.73m² [IQR 166; 182] and 29 (34%) with albuminuria (median 5.5 mg/mmol [IQR 3.7; 6.7]). There was not a statistically significant difference between SCN and non-SCN groups regarding urinary osmolarity, calcium reabsorption rate and TmP/GFR. However, the mean chloride, sodium and magnesium reabsorption rates were significantly higher in the group with SCN, with respectively 99.06 vs 98.74 (p-value = 0.01), 99.51 vs 99.31 (p-value < 0.01), 97.98 vs 97.49 (p-value = 0.04). The mean potassium reabsorption rate also tended to be higher in the SCN group: 91.72 vs. 89.95 (p-value = 0.05). Conclusions: Children with SCN seem to have a greater tubular reabsorption activity compared to those with normal glomerular function but exhibit similar renal concentrating ability, and urinary calcium and phosphorus excretion.