Assessment of Liver Fibrosis by Transient Elastography in Children and
Young Adults with Sickle Cell Disease With and Without Iron Overload
Abstract
Objectives: Transfusion-associated iron overload may cause liver
fibrosis. We compared transient elastography (TE) and aspartate
aminotransferase-platelet ratio index (APRI), non-invasive markers for
hepatic fibrosis, to percutaneous liver biopsy in children and young
adults with sickle cell disease (SCD). Methods: Subjects had serum
ferritin was >500 ng/mL and lacked history of viral
hepatitis. APRI scores, FerriScan® R2-MRI, liver biopsies, and TEs were
obtained. Hepatic fibrosis was scored according to Metavir system.
Age-matched controls with SCD but without iron overload were enrolled
for APRI and TE assessments. Results: Nineteen subjects (cases: 12
males, 7 females), ages 10-21 years (mean 15.9 years), were transfused
an average of 9.67 years, had a mean serum ferritin of 4,899±2849 ng/mL
(range 693-11,604 ng/mL), and a liver iron concentration (LIC) of
8.46±3.95 mg/g dry liver weight by R2-MRI. Mean APRI was 0.33±0.13
(0.13-0.61) in cases and 0.27±0.10 in five controls. The mean liver
stiffness measures (LSM) in cases, assessed by TE, was 8.46±3.95 kPa,
ranging from 3.5-14.6 kPa (expected normal less than 7 kPa). Controls
had a mean LSM of 5.72±1.74 kPa (4.6-8.7 kPa). Comparison of LSM to
histological fibrosis for cases revealed a T-value of 6.94,
p<0.0001. There was no significant correlation between APRI
and histological fibrosis and between LSM and APRI or LSM and ferritin.
Conclusion: TE measures but not APRI significantly correlated with
histologic fibrosis. Although the small sample size limits
generalization, LSM > 10 kPa suggests liver fibrosis in
children and young adults with SCD and may merit histologic confirmation
especially if persistent.