Elastography for the diagnosis of severity of fibrosis in chronic liver disease: A meta-analysis of diagnostic accuracy

Background & Aims: Transient elastography is a non-invasive method, for the assessment of hepatic fibrosis, developed as an alternative to liver biopsy. We studied the performance of elastography for diagnosis of fibrosis using meta-analysis. Methods: MEDLINE, EMBASE, SCI, Cochrane Library, conference abstracts books, and article references were searched. We included studies using biopsy as a reference standard, with the data necessary to calculate the true and false positive, true and false negative diagnostic results of elastography for a fibrosis stage, and with a 3-month maximum interval between tests. The quality of the studies was rated with the QUADAS tool. Results: We identified 40 eligible studies. Summary sensitivity and specificity was 0.79 (95% CI 0.74-0.82) and 0.78 (95% CI 0.72-0.83) for F2 stage and 0.83 (95% CI 0.79-0.86) and 0.89 (95% CI 0.87-0.91) for cirrhosis. After an elastography result at/over the threshold value for F2 or cirrhosis (positive result), the corresponding post-test probability for their presence (if pre-test probability was 50%) was 78%, and 88% respectively, while, if values were below these thresholds (negative result), the post-test probability was 21% and 16%, respectively. No optimal stiffness cut-offs for individual fibrosis stages were validated in independent cohorts and cut-offs had a wide range and overlap within and between stages. Conclusions: Elastography theoretically has good sensitivity and specificity for cirrhosis (and less for lesser degrees of fibrosis); however, it should be cautiously applied to everyday clinical practice because there is no validation of the stiffness cut-offs for the various stages. Such validation is required before elastography is considered sufficiently accurate for non-invasive staging of fibrosis. (C) 2010 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.