RENAL LENGTH IN SICKLE-CELL DISEASE - OBSERVATIONS FROM A COHORT STUDY

Renal length has been measured by ultrasound in 237 subjects with homo zygous sickle cell (SS) disease, 147 with sickle cell-hemoglobin C (SC ) disease, and in 78 age-matched controls with a normal hemoglobin (AA ) genotype. As expected, renal length increased with age in all genoty pes but mean length was significantly greater in SS disease compared w ith SC disease (mean difference 4.3 mm after adjustment for height) an d significantly greater in both genotypes than in AA controls (SS/AA d ifference 9.2 mm, SC/AA difference 5.0 mm after adjustment for height) . Examination of relationships between renal length and some hematolog ical indices (hemoglobin, fetal hemoglobin, reticulocyte counts, alpha thalassemia status) in SS or SC disease showed only a significant neg ative correlation with hemoglobin and positive correlation with reticu locyte count in SS disease. Further analysis suggested that the strong er relationship was between renal length and high reticulocyte count. The mechanism of renal enlargement is unknown although glomerular hype rtrophy and increased renal blood volume are likely contributors.