Longitudinal Transient Elastography Measurements Used in Follow-up for Patients with Cystic Fibrosis

Cystic fibrosis-related liver disease (CFLD) is diagnosed using a combination of criteria. Transient elastography (TE), an ultrasonographic method to evaluate liver stiffness, can differentiate patients with and without liver disease. This retrospective study (2007-2013) aimed to detect developing CFLD using consequent TE measurements. All cystic fibrosis patients with TE measurements between 2007 and 2013 (n = 150, median age 17 (9-24) y) were included, of which 118 had a median of three (range, 2-4) measurements with an interval of 1 (1-2) y. Twenty (14%) had CFLD at the first TE measurement; five (3%) developed CFLD during follow-up. The median TE value in CFLD was 14 kPa (8.7-32.2) compared with 5.3 (4.9-5.7) in cystic fibrosis patients without liver disease (CFnoLD; p = 0.0001). In CFnoLD, TE was correlated with age (p = 0.031). A TE result >6.8 kPa had a sensitivity of 91.5% and a specificity of 91.7% in predicting CFLD, according to the receiver operating characteristics analysis. It also has a positive predictive value of 88.6% and a negative predictive value of 86.9%, increasing to 91.7% and 98%, respectively, in patients at risk (<14 y) for developing CFLD. Patients with developing CFLD had progressively increasing consecutive TE measurements.