Chronic Kidney Disease and Albuminuria in Children with Sickle Cell Disease

Background and objectives Sickle cell nephropathy begins in childhood and may progress to renal failure. Albuminuria is a sensitive marker of glomerular damage that may indicate early chronic kidney disease (CKD). Design, setting, participants, & measurements The aims of this study were to determine the cross-sectional prevalence and clinical correlates of albuminuria and CKD among children with sickle cell disease (SCD). Over a 10-year period (1995 to 2005) 410 pediatric SCD patients ages 2 to 21 years were enrolled: 261 with hemoglobin SS (HbSS) or HbS beta(0) thalassemia (HbS beta(0)) and 149 with HbSC or HbS beta(+) thalassemia (HbS beta(+)). The albumin/creatinine ratio (ACR) of spot-urine specimens and serum creatinine were measured; abnormal albuminuria was defined as urinary ACR >= 30 mg/g. Results The prevalence of abnormal albuminuria was 20.7% (23.0% in HbSS/HbS beta(0), 16.8% in HbSC/HbS beta(+)). Among HbSS/HbS beta(0), abnormal albuminuria was associated with increasing age and lower baseline hemoglobin. GFR, estimated in 189 patients using the updated Schwartz formula, correlated negatively with age (r = -0.27, P = 0.0002). CKD defined according to the Kidney Disease: Improving Global Outcomes study was present in 26.5% (50 of 189) of patients: stage 1 in 27 (14.8%) and stage 2 in 22 (11.6%). In multivariate analysis, age and HbSC/HbS beta(+) genotype were associated with CKD. Conclusions This is the first study to stage CKD in children with SCD and highlights a high prevalence of albuminuria and glomerular injury early in life. Detecting CKD in childhood could allow for earlier intervention and prevention of renal failure in adulthood. Clin J Am Soc Nephrol 6: 2628-2633, 2011. doi: 10.2215/CJN.01600211