Noninvasive diagnostic methods of liver fibrosis in patients with primary biliary cirrhosis and primary sclerosing cholangitis: role of indirect serological markers

Aim of investigation. Considering prognostic value and dynamic nature of liver fibrosis in chronic cholestatic diseases: primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC), severity assessment by liver biopsy and/or noninvasive methods should be obligatory component of the investigation plan during patient follow-up to estimate treatment response. The aim of the present study was to evaluate diagnostic value of noninvasive tests based on indirect liver fibrosis serological markers for the estimation of fibrosis severity in PBC and PSC. Materials and methods. Original study was based on retrospective evaluation of 95 patients with PBC and 27 patients with PSC. According to routine laboratory test data and abdominal ultrasound, indexes of AST to ALT ratio (AAR); AST to platelet count ratio (APRI); platelet count to the spleen diameter ratio - PLT/ SPD and Fibrosis-4 score index (FIB-4) were calculated. All patients underwent liver biopsy with fibrosis stage assessment in biopsy specimen (METAVIR scale). Diagnostic value of estimated indexes was evaluated and compared by ROC-analysis with ROC-curve plotting and calculation of the area under the ROC-curve (AUROC). Results. In PBC group (median age Me [interquartile range] was 54 years [49-62]) 50,5% (n=48) of patients had significant liver fibrosis (F≥2) and 21,1% (n=20) - liver cirrhosis (F4). In PSC group (Me=40 [28-50] years) 63% of patients (n=17) had severe fibrosis (F≥2) and 33,4% (n=9) - and liver cirrhosis (F4) respectively. PLT/SPD index provided the highest AUROC values at significant fibrosis (F≥2), severe fibrosis (F≥3) and liver cirrhosis (F4) in PBC group (0,763 [95% CI 0,664- 0,861], 0,764 [0,662-0,866], and 0,805 [0,694-0,915], respectively). However in PSC group, highest AUROC was found for FIB-4 index (0,844 [0,682-1,000], 0,845 [0,698-0,993], and 0,785 [0,594-0,975], respectively). Conclusion. Application of FIB-4 index in PSC allows to reveal significant liver fibrosis stage (F≥2) with high accuracy (80,7%). Efficacy of other indexes (AAR, APRI, and PLT/SPD) in these patients, as well as AAR, APRI, FIB-4, and PLT/SPD indexes in PBC, should be characterized as quite low that makes their clinical application inexpedient