Application of transient elastometry to differentiate mild from moderate to severe liver fibrosis in HIV/HCV co-infected patients

Background/Aims Transient elastometry (TE) is accurate for detecting cirrhosis (F = 4) in human immunodeficiency virus (HIV)/hepatitis C virus (HCV) co-infected patients. However, this procedure is less precise to differentiate mild (F 1) from moderate to severe (F 2) fibrosis using the cut-off value of 7.2 kPa, a level previously proposed by some authors. Because of this, we elaborated and validated cut-off values of liver stiffness (LS) to better discriminate F 1 from F 2 in HIV/HCV co-infected subjects to aid therapy decisions. Methods One hundred and ninety-seven co-infected patients with liver biopsy and TE measurement, without prior therapy against HCV infection, were included. Results To diagnose F 2, a cut-off of 9.0 kPa showed a positive predictive value of 87%. To discard F 2, a cut-off of 6.0 kPa showed a negative predictive value of 90%. Considering all the patients, 61 (31%) patients yielded LS values 6.0 kPa and 81 (41%) patients showed LS values 9.0 kPa. There were no severe classification errors as the NPV of LS 6.0 kPa for F 3 was 100% and the NPV LS 9.0 kPa for F = 0 was also 100%. Conclusions The usefulness of TE can be enhanced using two different cut-off values to identify patients with F 1 and F 2.