Controlled attenuation parameter: A measure of hepatic steatosis in patients with cystic fibrosis.

BACKGROUND: Hepatic steatosis is a common manifestation of CF-related liver disease(CFLD). Controlled attenuation parameter(CAP) measurement during transient elastography(TE) semiquantifies liver steatosis. We examined the relationship between CAP and CFLD severity, clinical factors and liver stiffness measurements(LSM). METHODS: This is a cross-sectional study of CF patients seen for outpatient care between January 2013-March 2014. CFLD severity was categorized as no CFLD, CFLD without portal hypertension(PHTN) and CFLD with PHTN, based on published criteria. RESULTS: 129 patients (median 18.4y; 57% male) had valid CAP. 70(54%) had no CFLD, 44(34%) CFLD without PHTN, and 15(12%) CFLD with PHTN. The median CAP was 210 dB/m (IQR 181-239). Steatosis(CAP ≥230 dB/m) was seen in 27% of subjects without CFLD, 48% in CFLD but no PHTN, and 20% in with CFLD and PHTN(P = .04). CAP was higher for subjects with CFLD without PHTN (P < .05). There was no CAP difference between subjects with no CFLD and those with CFLD and PHTN (P ≥ .65). LSM was not different between no CFLD and CFLD without PHTN (P = .07), but each of these groups had lower LSM compared to subjects with CFLD and PHTN(P < .001 for each). Except for direct bilirubin, CAP was not associated with clinical markers of liver disease. CONCLUSION: CAP was normal in 86(67%) of patients with CF and was not associated with standard clinical markers of liver disease. CAP was higher in patients with liver disease, which could possibly reflect the loss of steatosis observed with progression to cirrhosis and portal hypertension.

Validation of Transient Elastography Cut Points to Assess Advanced Liver Fibrosis in Children and Young Adults: The Boston Children's Hospital Experience.

OBJECTIVE: To derive an optimal liver stiffness measurement cut point to discriminate METAVIR fibrosis stage F4 and to validate both METAVIR fibrosis stage F3-F4 and F4 cut points in a separate cohort. STUDY DESIGN: Patients at Boston Children's Hospital with liver stiffness measurement from 2006 to 2016 and liver biopsy ≤12 months before screening were eligible. Patients enrolled 2006-2011 were used to calibrate liver stiffness measurement cut points and those enrolled 2011-2016 for validation. Diagnostic performance was assessed by receiver operating curve analysis. RESULTS: In total, 267 subjects were enrolled (97 calibration, 170 validation). The cohorts were similar with 54% male, aged 0-29 years (median 13 years), and liver diseases including 21% autoimmune, 19% viral, 11% nonalcoholic fatty liver, 9% cholestatic, and 9% primary sclerosing cholangitis. Cut points to discriminate F3-F4 and F4 were >8.6 kPa and >11.5 kPa with 81% and 84% accuracy, respectively. Applied to the validation cohort, accuracy was 67% and 75%, respectively. In 44 fasted subjects, the accuracy was 73% and 80%, respectively. CONCLUSION: This study validates previously determined liver stiffness measurement cut points of 8.6 kPa and 11.5 kPa to predict METAVIR F3-F4 and F4 fibrosis in children and young adults in separate cohorts. With increasing data on the utility and validity of liver stiffness measurement in children, transient elastography may help identify patients with greater risk of advanced fibrosis and those who need liver biopsy assessment and/or surveillance for the complications of cirrhosis in a variety of liver disorders.

The Natural History of Primary Sclerosing Cholangitis in Children: A Large Single-Center Longitudinal Cohort Study.

OBJECTIVES: Data regarding pediatric primary sclerosing cholangitis (PSC) natural history are limited. We describe a large pediatric PSC cohort with longitudinal follow-up. METHODS: The present study records review of pediatric patients with PSC diagnosed between 1984 and 2014. RESULTS: N = 120 (63% M) ages 1 to 21 years (median 14 years) at diagnosis. 27% (31/113) had autoimmune sclerosing cholangitis (ASC), 24% had exclusive small duct PSC, METAVIR stage was F3-F4 in 41%. Eighty-one percent of patients with PSC had inflammatory bowel disease (IBD); most had ulcerative/indeterminate colitis (72/97), typically pancolitis (40/72). PSC-IBD was more common than ASC-IBD (85% vs 68%, P = 0.03). Median follow-up was 3.7 years (interquartile range [IQR] 1.5, 6.9). Median gamma glutamyl transferase decreased from baseline of 221 U/L (IQR 110, 425) to 104 U/L by 1 year postdiagnosis ([IQR 18,229], P < 0.0001), and then changed little. Mean fibrosis stage at diagnosis was 2.3 ±â€Š1.4 (N = 91), and at 1 to 5 years was 2.6 ±â€Š1.3 (N = 20). Transplant-free survival at 10 year was 89%; there were 6 liver transplants, 2 in patients with small duct PSC and 4 with diffuse large duct PSC. Although the cirrhosis rate was not significantly different in PSC with IBD versus without (22% vs 41%, P = 0.06), the former had a lower rate of liver transplantation (2% vs 18%, P = 0.01). The rate of cirrhosis was lower in patients diagnosed with IBD before PSC (15% vs 31%, P = 0.05). CONCLUSIONS: In this largest reported pediatric PSC cohort, liver transplantation rate at 10 years was lower than that reported in adults. ASC and PSC had similar biochemical abnormalities and degree of fibrosis at diagnosis. PSC that developed after IBD diagnosis had a milder course, possibly reflecting earlier disease detection or milder phenotype.