Relationship between microalbuminuria and glomerular filtration rate in children with sickle cell anemia in steady state

Background: Microalbuminuria (MA), a common phenomenon in children with sickle cell anemia (SCA), is defined as an increased urinary albumin-creatinine ratio of 30-300 mg/g of creatinine in an early morning or random urine specimen. Whereas some studies have shown that MA reflects early kidney damage, other studies have documented that it is a manifestation of advanced nephropathy. The reports about the relationship between glomerular filtration rate (GFR) and MA in children with SCA are conflicting. Materials and Methods: This was a longitudinal study. Serum creatinine, GFR, and albumin-creatinine ratio were determined at baseline. The individuals were followed up over 3 months during which albumin-creatinine ratio and GFR were assayed monthly, and the relationship between them was determined. Results: One hundred and seventy children aged 1-18 years with SCA and MA were studied. The mean albumin-creatinine ratio was 120.9 ± 66.8 mg/g, 138.32 ± 101.79 mg/g, 117.12 ± 78.09 mg/g, and 106.73 ± 38.82 mg/g at baseline, 1, 2, and 3 months, respectively, whereas the mean GFR was 121.7 ± 33.0 ml/min/1.73 m2, 117.69 ± 29.70 ml/min/1.73 m2, 117.56 ± 35.77 ml/min/1.732 m2, and 116.22 ± 30.28 ml/min/1.73 m2 at baseline, 1, 2, and 3 months, respectively. There was no significant relationship between MA and GFR in the participants throughout the study period (Pearson's correlation coefficients: 0.050, 0.250, 0.268, and 0.143 and corresponding P: 0.95, 0.88, 0.15, and 0.36). Conclusions: GFR is normal in SCA children with MA. There is no significant relationship between MA and GFR in children with SCA.