Chronic hepatitis C and liver fibrosis

Table 1 Factors contributing to fibrosis progression in chronic hepatitis C

Non-modifiable	Modifiable
Duration of HCV infection	High alcohol consumption (≥ 20-50 g/d)
Older age at infection	Insulin resistance
Male sex	Obesity
Presence of baseline fibrosis	Metabolic syndrome
HIV or HBV co-infection	Daily cannabis use
Infection with HCV genotype 3
Gene polymorphisms involved in iron overload/inflammatory pathways
Latin ethnicity

HCV: Hepatitis C virus; HIV: Human immunodeficiency virus; HBV: Hepatitis B virus.

Table 2 Comparison of the main characteristics of liver biopsy, serum biomarkers and transient elastography

	Liver biopsy	Serum biomarkers	Transient elastography
Advantages	Direct assessment of liver fibrosis	Immediate result	Immediate result
	Stage by stage fibrosis classification	Fast (one time blood sample)	Duration of examination 5 min
	Evaluation of coexisting disorders (inflammation, steatosis, iron overload)	Patient friendly	Operator and patient friendly
Limitations	Complications (pain, bleeding)	Cost (unitary cost per patient for patented tests)	Cost (one time per machine)
	Sampling error, intra-observer and inter-observer variability	High rates of unclassified patients (APRI, Fib-4, Forns’ index, Lok index)	Failure in 5% of cases (25% in obese patients)
	Hospitalization (day hospital) often required		Unreliable results in 15% of cases (obesity, ascites, limited operator experience)
	Cost	Lower performance for diagnosis of significant fibrosis	Lower performance for diagnosis of significant fibrosis
	Delayed result (2-4 wk)	Unable to discriminate between intermediate stages of fibrosis	Unable to discriminate between intermediate stages of fibrosis
Contraindications	Absolute: uncooperative patient, severe coagulopathy, extrahepatic biliary obstruction	None	Pacemaker, pregnancy
	Relative: ascites, morbid obesity, possible vascular lesions, amyloidosis
Risk factors for error	Biopsy sample < 2 cm in length, containing < 10 complete portal tracts; inexperienced pathologist	Autoimmune thrombocytopenia (APRI); Gilbert’s sydrome, extrahepatic cholestasis, hemolytic anemia (Fibrotest)	Transaminases flares; acute viral hepatitis; non-fasting patient; vascular hepatic congestion; extrahepatic cholestasis; IQR ≥ 30%

APRI: Aspartate aminotransferase to platelet ratio index; IQR: Interquartile range.

Table 3 Role of liver biopsy and non-invasive tools across the international guidelines

Ref.	Threshold for definitive indication to antiviral therapy	Recommended methods for liver fibrosis staging	Can non-invasive methods replace liver biopsy?
APASL[109], 2007	F1	Liver biopsy	No
AASLD[190], 2009	F2	Liver biopsy, serum biomarkers, transient elastography	No
EASL[81], 2014	F2	Liver biopsy, serum biomarkers, transient elastography	Yes
CASL[111], 2012	None	Liver biopsy, serum biomarkers, transient elastography	Yes

Table 4 Main validation features among the non-invasive methods for liver fibrosis diagnosis

Ref.	Parameters	Independent validation studies	Etiology-validation studies	Characterization of risk factors for error	Validation in special HCV populations
AAR[138]	AST, ALT	+	+	+	+
APRI[142]	AST, platelets	+	+	+	+
ELF[131]	Age, TIMP-1, hyaluronan, procollagen type III	+/-	+	+	-
Fib-4[145]	Age, ALT, AST, platelets	+	+	+	+
Fibrometer®[122]	Platelets, prothrombin index, AST, α2-macroglobulin, hyaluronan, urea, age	+/-	+	+	+
Fibroscan®[167]	Liver stiffness measurement	+	+	+	+
Fibrospect®[132]	Hyaluronan, TIMP-1, α2-macroglobulin	+/-	-	-	-
Fibrotest-Fibrosure®[132]	γGT, total bilirubin, haptoglobin, α2-macroglobulin, apolipo-protein A1, age, gender	+	+	+	+
Forns’ index[144]	Age, γGT, cholesterol, platelets	+	+	+	+
Hepascore[129]	Age, gender, bilirubin, γGT, hyaluronan, α2-macroglobulin	+/-	+	-	+
Hyaluronan	Hyaluronic acid	+	+	+	+
Lok index[191]	AST, ALT, platelets	-	-	+	-

AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; AAR: AST-to-ALT ratio; APRI: AST-to-platelet ratio index; AP: Age-to-platelet ratio; HCV: Hepatitis C virus; TIMP-1: Tissue inhibitors of metalloproteinases-1.

Table 5 Diagnostic performance of serum biomarkers in chronic hepatitis C

Index	≥F2/F4
	AUC	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	LR+	LR-
Hyaluronan[113-115,119,128]	0.73-0.86/ 0.89-0.92	64.5-75/ 79.2-100	81.0-91.2/ 80.0-89.4	44.0-86.3/ 63.0-100	78.5-93/ 99.0-100	3.94-7.32/ 5.00-7.47	0.30-0.38/ 0.00-0.23
Fibrometer[122,124]	0.85-0.89/ 0.91	80.5-89/ 94.1	84.1-89.9/ 87.6	82.0-86.3/ 68	77.6-82.5/ 94.7	5.56-7.97/ 7.46	0.13-0.21/ 0.06
FibroSpect[122,126-128]	0.82-0.87/ NA	71.8-93.0/ NA	66.0-73.9/ NA	60.9-82.6/ NA	77.7-94/ NA	2.73-2.75/ NA	0.10-0.24/ NA
Hepascore[124,129,130]	0.79-0.85/ 0.85-0.94	53.08-82/ 71.0-76.5	65.0-92.0/ 84.0-89.8	70-88/ 64.9	63.5-78/ 89.6-98	2.34-6.62/ 4.78-6.96	0.27-0.51/ 0.27-0.32
ELF score[122,131]	0.80/ NA	90/ NA	31/ NA	27.5/ NA	92/ NA	1.30/ NA	0.32/ NA
AAR[137,192]	NA/ 0.51-0.83	NA/ 46.7-78.0	NA/ 95.9-100	NA/ 73.7-100	NA/ 80.7-89	NA/ 19.02	NA/ 0.22-0.43
APRI[122,124,133,137,142,192-194]	0.69-0.88/ 0.61-0.94	41-91/ 57-89	47-95/ 75-93	61-88/ 38-57	64-86/ 93-98	1.71-8.20/ 3.56-8.14	0.19-0.62/ 0.10-0.46
Lok Index[137,191]	NA/ 0.78-0.81	NA/ 37-92	NA/ 30-94	NA/ 32-75	NA/ 84-91	NA/ 1.31-6.16	NA/ 0.26-0.67
Forns’ Index[122,124,133,144,192,193]	0.60-0.86/ NA	79.8-94/ NA	61.2-95.0/ NA	66-94.7/ NA	63.8-96/ NA	2.42-15.96/ NA	0.09-0.21/ NA
Fib-4[145]	0.82-0.89/ 0.79-0.91	37.6-74.3/ NA	80.1-98.2/ NA	82.1/ NA	94.7/ NA	3.73-20.77/ NA	0.32-0.63/ NA
Fibrotest[122,124,132,133,135]	0.74-0.87/ 0.71-0.87	65-77/ 50-87	72-91/ 70-92.9	76-80/ 57.9-93	66.7-81/ 44-90.5	2.75-7.22/ 2.9-7.04	0.31-0.38/ 0.17-0.53

AUC: Area under the curve; NA: Not available; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; AAR: AST-to-ALT ratio; APRI: AST-to-platelet ratio index.

Table 6 Cut-off values, performance and number of patients per study of Fibroscan^®

Ref.	Cut-off for≥F2 (kPa)	Cut-off for F4 (kPa)	AUC for≥F2	AUC for F4	Number of patients included
Sandrin et al[147], 2003	7.6	14.4	0.88	0.99	106
Castéra et al[167], 2005	7.1	12.5	0.83	0.95	183
Ziol et al[195], 2005	8.7	14.5	0.79	0.97	327
Kettaneh et al[196], 2007	6.8	17.6	0.79	0.91	935
Arena et al[197], 2008	7.8	14.8	0.91	0.98	150
Cross et al[198], 2010	8.9	10.1	0.89	0.97	187
Degos et al[199], 2010	5.2	12.9	0.75	0.90	913

AUC: Area under the curve.

Table 7 Combination algorithms of non-invasive methods for liver fibrosis proposed in chronic hepatitis C

Algorithm’s name	Type	Non-invasive methods adopted	AUC for≥F2	AUC for F4	Saved liver biopsies for > F2 (%)	Saved liver biopsies for F4 (%)	Number of studies (patients)
SAFE biopsy[133,165]	Stepwise	APRI, Fibrotest®	0.89-0.94	0.87-0.92	43.8-54.0	74.8-93.4	6 (4118)
Bordeaux algorithm[167,168]	Synchronous	Fibrotest, Fibroscan®	0.88-0.91	0.93-0.95	71.9-77.0	78.8-79.0	3 (875)
Leroy algorithm[124]	Synchronous	APRI, Fibrotest®	0.94	NA	19.0-29.2	NA	3 (1381)
Fibropaca algorithm[134]	Synchronous	APRI, Fibrotest, Forns’ index	0.88	0.85	51.7	76.2-81.3	2 (1248)
Angers algorithms[171]	Synchronous	Fibrotest, Fibrometer®	0.892	0.917	79.8	89.7	1 (390)
Bourliere’s algorithm[166]	Stepwise	APRI, Hepascore	91%-96% (accuracy)		33-45		1 (467)
Fibrometer® + Fibroscan[172]	Synchronous	Fibrometer, Fibroscan	86.7%		100		1 (1785)

APRI: Aspartate aminotransferase to platelet ratio index; NA: Not available.