Heterogeneous ultrasound may predict risk for advanced liver disease in cystic fibrosis
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A heterogeneous ultrasound pattern may identify children with cystic fibrosis at high risk for development of advanced liver disease.
Final results of the PUSH study, which evaluated whether a heterogeneous ultrasound pattern could be used to predict risk for advanced liver disease, indicated by a nodular liver ultrasound, within 6 years in children with cystic fibrosis, were reported at the North American Cystic Fibrosis Conference.
“About 7% of children [with cystic fibrosis] will eventually develop advanced liver disease, primarily cirrhosis, although some may be noncirrhotic portal hypertension. Most of these complications develop by [age] 10 and very few are diagnosed after [age] 20,” Michael R. Narkewicz, MD, professor at the University of Colorado and pediatric transplant hepatologist at the Children’s Hospital of Colorado, Aurora, said during the presentation. “We were looking for a marker that could predict individuals at risk for the development of advanced [cystic fibrosis liver disease].”
PUSH was a prospective, matched-cohort study that enrolled 774 children with cystic fibrosis and pancreatic insufficiency aged 3 to 12 years at 11 cystic fibrosis centers in the U.S. and Canada from 2010 to 2014. There was one radiologist assigned per site for the duration of the study. Radiologists underwent standardized training. Each patient underwent a standardized ultrasound at baseline, which was interpreted and scored by consensus of four study radiologists as normal, heterogeneous, homogeneous increased echogenicity or nodular, Narkewicz said.
Children with a heterogeneous ultrasound pattern (n = 55) were matched with two children with a normal ultrasound (n = 116) by age, pseudomonas status and center. All participants underwent yearly clinical exams, laboratory testing and biospecimen collections, and a standardized ultrasound every other year during the 6-year study.
The primary outcome was development of an advanced liver disease pattern on ultrasound by year 6, as graded by two of three radiologists.
Narkewicz presented results from 62 children who had a heterogeneous ultrasound pattern and 123 who had a normal pattern on the initial screen. Those with a heterogeneous pattern had abnormal gamma-glutamyl transpeptidase (GGTP), alanine aminotransferase (ALT) and lower platelets and a higher aspartate aminotransferase to platelet ratio index (APRI) and fibrosis-4 (FIB-4) index.
By 6 years of follow-up, the RR for a nodular ultrasound pattern was 33% in those with a heterogeneous consensus grade at the initial screening ultrasound compared with 3% in those with a normal pattern at the initial screen (RR = 9.5; 95% CI, 3.4-26.7; P < .0001), Narkewicz said. The researchers also performed univariate and multivariate logistical regression analysis adjusted for ultrasound grade at screening and found that including variables such as age, GGTP, ALT and APRI improved the discrimination measure C-index.
“This suggests that research ultrasound imaging could be used to identify a cohort of young cystic fibrosis subjects with a high risk of progressing to advanced liver disease. This opens the door to development of preventive therapeutic trials targeting a cystic fibrosis liver disease. This does not indicate the clinical ultrasound with a single reader will be associated with the same predictive ability,” the researchers concluded in their poster.