Hydroxyurea and Regression of Sickle Cell Nephropathy

Key Points Sickle cell nephropathy regression. Hydroxyurea action on sickle cell nephropathy. Background Renal complications of sickle cell disease are becoming very common, and patients generally do not respond to conventional nephroprotective treatments. Among the drugs used, hydroxyurea (HU) seems to have produced good results according to some studies. This molecule has not yet been evaluated in the Democratic Republic of Congo to evaluate albuminuria and GFR after 9 months of HU treatment in a population of children with incipient sickle cell nephropathy (SCN). Methods This was an open clinical trial involving sickle cell syndrome children younger than 18 years followed by incipient SCN (glomerular hyperfiltration [GHF] and/or microalbuminuria). A mean HU dose of 20 mg/kg per day was administered to each child, with quarterly clinical and biologic controls. GHF (new Schwartz formula) was defined as a rate >130 ml/min per 1.73 m 2 for girls and >140 ml/min per 1.73 m 2 for boys; albuminuria was defined as the albuminuria/creatinuria ratio in mg/g. The Wilcoxon and McNemar tests were used to compare the results at admission and at the ninth month of treatment. Results In total, 30 children (mean age 8.9±4.1 years; 40% boys) whose mean fetal hemoglobin level increased from 10%±7.4% to 18.8%±4.9% ( P < 0.001), mean number of blood transfusions ranged from 7.4±6.7 to 0.1±0.3 bags/mo ( P < 0.001), and number of vaso-occlusive crises ranged from 1.8±1.1 to 0.2±0.4/mo ( P < 0.03) were included. The frequency of GHF decreased from 30% to 3.3% ( P < 0.001). The mean albuminuria decreased from 122.5±16.3 to 30±2.4 mg/g. Conclusions HU improved the course of SCN. The mechanism of action behind this result seems to be an improvement in blood rheology.