Assessment of Kidney Size in African American Children with Sickle Cell Disease: A Matched-Pair Analysis

Background: Sickle cell disease (SCD) is caused by a beta-globin gene mutation that produces sickling of red blood cells. Increase in cardiac output from sickle cell anemia produces hyperfiltration that results in a progressive increase in renal size. We aim to examine the impact of SCD morbidity on kidney size using renal ultrasound. Methods: The study included 31 African Americans with SCD aged 3 to 20 years and 57 matched controls who were seen in outpatient clinic from 01/ 2018 to 12/2022. Cases were matched with controls at 1:2 ratio. We examined the impact of the severity of hemoglobinopathy on kidney size by stratification of subjects based on HBSS and HBSC subtypes, and SCD morbidity score. Results: Four subjects had HBSC and 27 had HBSS genotypes. The right and the left kidney volume of SCD cases were significantly larger than of controls [p < 0.0001] (Table 1). There was a significant difference in eGFR between subjects and controls, and among individuals with HBSS and HBSC genotypes (Table 1 and Fig. 1). A unit increase in SCD morbidity score was associated with 5.7 and 5.1 cm3 volume increase for right and left kidneys respectively. Conclusion: Severity of sickle cell anemia positively correlates with a greater eGFR and (therefore) volume of hyperfiltration, which in turn, are the primary determinants of nephromegaly.Fig 1: Box plot of eGFRs for the difference between matched subjects by hemoglobin genotypes.