Cystatin C-derived estimated glomerular filtration rate in children with sickle cell anaemia

BACKGROUND: Sickle cell disease is the most common inherited blood disorder in humans and constitutes a major public health burden. It is a multisystemic condition with long-term renal complications. Early detection of sickle cell nephropathy and initiation of appropriate interventions are associated with improved survival and quality of life. This study aimed to compare the cystatin C-derived estimated glomerular filtration rate (GFR) of the study groups and also, to correlate the clinical features of chronic kidney disease (CKD) with decreased GFR in children with sickle cell anaemia (SCA). METHODS: This hospital-based cross-sectional analytic study recruited 86 SCA subjects in steady-state and 86 age and sex-matched healthy HbAA controls aged 1–14 years who attended the Paediatric Haematology and Outpatient clinics of Federal Medical Centre Bida over six months. Data were collected using a semi-structured questionnaire, and participants’ length/height, weight, and blood pressure were measured using standard procedures. Blood samples were drawn for serum cystatin C assay via the sandwich enzyme-linked immunosorbent assay (ELISA) technique. Filler’s equation was used to calculate the glomerular filtration rate. RESULTS: There was a significant difference in the mean cystatin C-derived GFR between the two groups, i.e. 116 ± 30mL/min/1.73m(2) vs. 106 ± 24mL/min/1.73m(2) for the SCA and control groups, respectively (p = 0.017). The prevalence of supernormal GFR (i.e. GFR > 140mL/min/1.73m(2)) and decreased GFR (i.e. GFR < 90mL/min/1.73m(2)) was 19.8% and 22.1%, respectively, in children with SCA. There was no significant association between the age at diagnosis of SCA, blood transfusions, blood pressure, packed cell volume and presence of peripheral oedema with decreased GFR in the study subjects. CONCLUSIONS: Supernormal GFR is common in children with SCA and there is no significant association between clinical features of CKD with decreased GFR. Regular evaluation of renal function is, however, recommended in children with SCA for early detection and treatment of renal complications in order to halt the progression to end-stage kidney disease (ESKD).