2D Shear Wave Elastography, a promising screening tool for Cystic Fibrosis liver disease, shows a correlation between vitamin D and liver stiffness

Abstract

Background: Liver disease in Cystic Fibrosis (CFLD) is an early complication of CF. Evidence of CFLD is often subclinical and screening is recommended. Screening includes a biochemical work-up and an ultrasound investigation. Non-invasive methods measuring liver stiffness such as shear wave elastography could be beneficial. This study describes the use of 2D Shear Wave Elastography (2D SWE) in screening for CFLD in a clinical setting and explores its correlation to other indicators of CFLD. Furthermore, a relationship between liver stiffness and nutritional status, lung function and glucose tolerance was explored.

Material and methods: A retrospective cohort study was performed at a pediatric CF center. Information was gathered from the patients' charts and the Swedish national CF registry. The patients included had been evaluated for the presence of CFLD by ultrasound and 2D SWE during 2018-2020. Demographic data as well as data concerning nutritional status, lung function and glucose tolerance were collected.

Results: Fifty-one subjects were included with a median age of 11 years. Four children who had biopsy confirmed liver cirrhosis had significantly increased liver stiffness. There was a statistically significant negative correlation between liver stiffness and vitamin D levels and FEV1% predicted respectively. Children with abnormal glucose tolerance had increased liver stiffness compared to their normal glucose tolerant counterparts.

Conclusion: Measuring liver stiffness by 2D SWE is a reliable addition to CFLD screening with data comparable to the more conventional ultrasound investigation. Increased liver stiffness is associated with lower vitamin D levels, lower FEV1% predicted and abnormal glucose tolerance.

Keywords: 2D Shear wave elastography; Cystic fibrosis liver disease screening; Liver stiffness; Vitamin D.