Comparison of Fibrotest and PGAA for the diagnosis of fibrosis stage in patients with alcoholic liver disease

Abstract

Background and aims: The PGAA index was one of the first composite liver fibrosis markers. This study aims, prospectively, to confirm the diagnostic value of PGAA and Fibrotest in patients with alcoholic liver disease and to compare their diagnostic performances.

Patients and methods: We prospectively included 200 consecutive patients (159 men and 41 women; mean age: 51±0.7 years).The PGAA index was calculated by combining the results of four laboratory tests (prothrombin time, γ-glutamyl transpeptidase, apolipoprotein A1, and α-2-macroglobulin) scored on a 0-4 scale. The Fibrotest score was computed using the Biopredictive website. The overall diagnostic performances of scores were evaluated in terms of the area under the receiver operating characteristic (AUROC) curve. The Obuchowski measure was assessed taking into account the distribution of fibrosis stages observed in the cohort.

Results: For predicting F≥2 fibrosis stage, the AUROC curves of PGAA and Fibrotest were 0.83±0.03 and 0.80±0.03, respectively. For predicting F4 fibrosis stage, the AUROC curves of PGAA and Fibrotest were 0.87±0.03 and 0.86±0.03. There was no difference between the AUROC curves of PGAA and Fibrotest. The Obuchowski measure was 0.92±0.01 for PGAA and Fibrotest. For a value of 10, PGAA had 98% specificity and 97% positive predictive value for the detection of F≥2 fibrosis stage and 80% sensitivity and 92% negative predictive value for F4 stage fibrosis.

Conclusion: We confirm the comparable diagnostic values of Fibrotest and PGAA. When Fibrotest use is constrained by an increase in unconjugated bilirubin or is not financially viable, PGAA may be an alternative.