Early blood transfusions protect against microalbuminuria in children with sickle cell disease

Background: Microalbuminuria (MA) is an early indicator for glomerulopathy in sickle cell disease (SCD). Procedure: We reviewed the medical records of asymptomatic patients ages 420 with sickle hemoglobinopathies, who were screened for MA in order to find out its prevalence and risk factors. Results: Nineteen of 120 (15.8%) screened patients had MA detected by spot urine (mean albumin absolute value 6.95 +/- 0.56 mg/dl) and abnormal albumin to creatinine ratios (79.8 +/- 0.62 mg/g creatinine). Twenty four-hour urine collections confirmed 57% of MA cases by spot urine. There was no difference in hyperfiltration between positive and negative patients. From the MA-positive patients, 15 had SS (16.8% of SS group) and 4 had SC (18% of SC group). Nineteen percent of children 10 years of age or older had MA, as compared to 8% of the younger children (P=0.018), demonstrating that increasing age is a risk factor for MA. There was a positive correlation between MA and acute chest syndrome. Young age at start of chronic transfusions was inversely related to MA and therefore renoprotective (P=0.03). We did not see a protective effect in the group of patients taking hydroxyurea for a relatively short time, mean age at start of treatment 12 +/- 5 years; however the sample was small. Conclusions: We conclude that: (1) children with sickle cell hemoglobinopathies 10 years or older should be screened for MA and (2) chronic transfusions starting at an early age may be renoprotective.