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Reproducibility of liver stiffness measurements in hepatitis C virus (HCV)-infected patients in Egypt

Authors


Nicolas Vignier, Unité d’Épidémiologie des Maladies Émergentes, Institut Pasteur, 25 rue du Docteur Roux, 75724, Paris Cedex 15, France. E-mail: vigniernicolas@yahoo.fr

Abstract

Summary.  Elastometry has demonstrated good accuracy, but little is known about its reproducibility. The aim of this study was to assess the intra- and inter-operator reproducibility of liver stiffness measurement among hepatitis C virus (HCV)-infected patients in Egypt. The study was conducted among HCV-infected patients referred for treatment evaluation in two hepatitis treatment centres of Cairo. Two operators took liver stiffness measurement two times per patient the same day. Intra- and inter-reproducibility were estimated by different methods: Bland and Altman graphics, variation coefficient, intraclass correlation coefficient and Kappa coefficient; 7.1 kPa was used as the threshold of significant (≥F2) fibrosis whenever needed. Fifty-eight patients were included in the study, and 216 measurements were taken. Failure rate was 7% and associated with overweight. For a value of 7.1 kPa, the inter-operator 95% limits of agreement were estimated at ±2.88 kPa. Intra- and inter-operator coefficients of variation ranged between 11% and 15%, intraclass correlation coefficients [95% confidence interval] between 0.94 [0.86–0.97] and 0.97 [0.95–0.99], and Kappa coefficients between 0.65 [0.44–0.88] and 0.92 [0.81–1.00]. The reliability of liver stiffness measurement is questionable when considering the decision to initiate antiviral therapy because of the percentage of discordance between measurements is notable, especially in the intermediate fibrosis stages.

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