Noninvasive strategies for metabolic dysfunction-associated steatotic liver disease assessment and referral in Japan

Table 1 Noninvasive tests for the diagnosis of liver fibrosis and activity used in Japan

Classification of NITs		Name of NITs
Scoring system		FIB-4 index
		NAFLD fibrosis score
Blood biomarkers	Liver-specific fibrosis markers	ELF test
		COL4-7S
		M2BPGi
		ATX
		HA
	Hepatocyte apoptosis marker	CK-18F (M30)

NITs: Noninvasive tests; FIB-4: Fibrosis-4; NAFLD: Non-alcoholic fatty liver disease; ELF: Enhanced liver fibrosis; COL4-7S: Type IV collagen 7S; M2BPGi: Mac-2-binding protein glycosylation isomer; ATX: Autotaxin; HA: Hyaluronic acid; CK-18F: Cytokeratin 18 fragment.

Table 2 Cutoff values for each noninvasive test according to liver fibrosis stage

	F2	F3	F4
ELF score	10.1	11.1	11.5
ELF score1 (for prediction of event)	-	9.8	11.3
M2BPGi (C.O.I./AU/mL)	1.15	0.99	1.71
COL4-7S (ng/mL)	3.8	4.8	6.6
VCTE1 (kPa)	-	Rule-in: 12 kPa. Rule-out: 8 kPa	Rule-in: 20 kPa. Rule-out: 8 kPa
MRE (kPa)	3.14	3.53	4.45

¹According to guidelines from the American Association for the Study of Liver Diseases and the European Association for the Study of the Liver-European Association for the Study of Diabetes-European Association for the Study of Obesity.

ELF: Enhanced liver fibrosis; M2BPGi: Mac-2-binding protein glycosylation isomer; C.O.I.: Cutoff index; COL4-7S: Type IV collagen 7S; VCTE: Vibration-controlled transient elastography; MRE: Magnetic resonance elastography.

Table 3 Statements and agreement degree in the Delphi round,

Number	Statements	Agreement 1st round	Agreement 2nd round
The usefulness of NIT in the treatment of MASLD
1-1	Known noninvasive markers and imaging tests that have been validated for MASLD have been verified in various cross-sectional studies, and their clinical application in Japanese MASLD cohorts would be highly useful	11 (100)	11 (100)
1-2	Known noninvasive markers and imaging tests that have been validated for MASLD have a lack of longitudinal studies, and further validation is needed to determine whether they can serve as prognostic markers or tests	11 (100)	11 (100)
1-3	Blood biomarkers and imaging diagnostics are useful for evaluating liver fibrosis, and if possible, non-hepatologists and even family physicians should use these to guide referral to a hepatologist	11 (100)	11 (100)
1-4	The occurrence of liver disease-related events in patients with MASLD depends on the degree of progression of liver fibrosis. Evaluation of liver activity (inflammation, necrosis, and fatty changes) in addition to evaluation of liver fibrosis is useful for evaluating the rate of progression of the disease	11 (100)	11 (100)
FIB-4 index
2-1	The FIB-4 index can be recommended as a first-line tool to screen for advanced fibrosis in patients with MASLD	11 (100)	11 (100)
2-2	A FIB-4 index > 1.3 is a reasonable criterion for referral to a hepatologist	4 (36.4)	0 (0)
2-3	The FIB-4 index is useful for predicting the prognosis of MASLD	11 (100)	11 (100)
ELF test
3-1	ELF is recommended in international guidelines to narrow down the range of cases of MASLD with advanced fibrosis, and should also be recommended in Japan	11 (100)	11 (100)
3-2	Evidence from cross-sectional studies of ELF in the assessment of MASLD liver fibrosis has been established for the diagnosis of fibrosis in Japanese patients with MASLD	7 (63.6)	5 (45.5)
M2BPGi
4-1	Evidence for the use of M2BPGi in the assessment of MASLD liver fibrosis has been established through a cross-sectional study of Japanese patients with MASLD	9 (81.8)	8 (72.7)
4-2	Longitudinal studies to predict the prognosis of patients with MASLD using M2BPGi are still lacking, and further validation is required	11 (100)	11 (100)
COL4-7S
5-1	COL4-7S can be used to diagnose advanced liver fibrosis in place of liver biopsy	11 (100)	11 (100)
5-2	Because COL4-7S is a single marker, it is less affected by fatty changes or ballooning hepatocytes, and reflects the state of fibrosis better than other markers	10 (90.9)	11 (100)
5-3	As the second step of FIB-4, COL4-7S is useful for identifying MASLD risk groups	11 (100)	11 (100)
5-4	For COL4-7S, it is necessary to set and verify a cutoff value for the current measurement method, the CLEIA method	11 (100)	11 (100)
CK-18F
6-1	MASL/MASH can be diagnosed using CK-18F	2 (18.2)	0 (0)
6-2	CK-18F is a valid marker for evaluating MAS as an index of liver activity	10 (90.9)	10 (90.9)
6-3	CK-18F can reflect the effects of various treatments by assessing liver activity	7 (63.6)	8 (72.7)
6-4	CK-18F can diagnose at-risk MASH	6 (54.5)	1 (9.1)
6-5	The combination of CK-18F and FIB-4 indexes is useful for diagnosing MASH	10 (90.9)	10 (90.9)
US elastography
7-1	Liver stiffness measured by VCTE can be used as the standard for evaluating liver fibrosis	9 (81.8)	7 (63.6)
7-2	2D-SWE measurements may be compatible with VCTE measurements	9 (81.8)	10 (90.9)
7-3	The effectiveness of treatment can be assessed based on changes in liver stiffness measured by VCTE	10 (90.9)	9 (81.8)
MRE
8-1	Liver stiffness measured by MRE may be used as the first line of treatment in routine clinical practice	1 (9.1)	0 (0)
8-2	Liver stiffness measurement by MRE could become the gold standard for clinical trials and research	11 (100)	11 (100)
8-3	It is possible to predict prognosis based on liver stiffness measured by MRE	11 (100)	11 (100)
8-4	The MEFIB score can efficiently diagnose F > 2	11 (100)	11 (100)
8-5	The MAST score can diagnose at-risk MASH	10 (90.9)	11 (100)
Genetic polymorphism
9-1	PNPLA3 gene polymorphism is involved in the progression of liver fibrosis	11 (100)	11 (100)
9-2	Measurement of gene polymorphisms is useful for assessing the risk of progression of liver fibrosis	10 (90.9)	11 (100)
Differentiated use by cohort
10-1	It is better for the NIT cutoff values to be the same in the health checkup cohort and the hospital cohort	5 (45.5)	2 (18.2)
10-2	If FIB-4 is < 1.3, observation is sufficient regardless of the cohort	9 (81.8)	4 (36.4)

Data are presented as n (%). NIT: Noninvasive test; MASLD: Metabolic dysfunction-associated steatotic liver disease; FIB-4: Fibrosis-4; ELF: Enhanced liver fibrosis; M2BPGi: Mac-2-binding protein glycosylation isomer; COL4-7S: Type IV collagen 7S; CLEIA: Chemiluminescent enzyme immunoassay; CK-18F: Cytokeratin 18 fragment; MASL: Metabolic dysfunction-associated steatotic liver; MASH: Metabolic dysfunction-associated steatohepatitis; MAS: Macrophage activation syndrome; US: Ultrasound; VCTE: Vibration-controlled transient elastography; 2D-SWE: Two-dimensional shear wave elastography; MRE: Magnetic resonance elastography; MEFIB: Magnetic resonance elastography combined with the fibrosis-4; MAST: Magnetic resonance imaging-aspartate aminotransferase; PNPLA3: Patatin-like phospholipase domain-containing 3.

Table 4 Cutoff scores in guidelines and clinical guidance for the enhanced liver fibrosis test

Guidelines/clinical guidance	Cutoffs for the ELF test
EASL-EASD-EASO Clinical Practice Guidelines[15]	Rule-out: 7.7
	Rule-in: 9.8
AASLD Practice Guidance[13]	Low risk: < 7.7
	Intermediate risk: 7.7-9.8
	High risk: > 9.8
ADA Guidelines[14]	Single cutoff: 9.8

ELF: Enhanced liver fibrosis; EASL: European Association for the Study of the Liver; EASD: European Association for the Study of Diabetes; EASO: European Association for the Study of Obesity; AASLD: American Association for the Study of Liver Disease; ADA: American Diabetes Association.

Table 5 Cutoffs for the enhanced liver fibrosis test

Ref.	Study design	Stage 1	Stage 2	Stage 3	Stage 4
Nobili et al[29], 2009	Cross-sectional	9.28	10.18	10.51	-
Inadomi et al[30], 2020	Cross-sectional	-	9.86	10.38	-
Seko et al[31], 2023	Cross-sectional	9.1	10.11	11.1	11.54
Sanyal et al[35], 2023	Cross-sectional	-	8.8/10.01	9.2/10.41	9.7/10.91
Hinkson et al[32], 2023	Meta-analysis	-	9.5	9.6	-
Vali et al[33], 2020	Meta-analysis	-	9.37	9.43	-
Sanyal et al[34], 2019	Longitudinal	-	-	9.82	11.32

¹Cutoff with sensitivity ≥ 90% and specificity ≥ 90%.

²Cutoff for the prediction of clinical event.

Table 6 Clinical utilities of the fibrosis-4 and type IV collagen 7S (radioimmunoassay) for the diagnosis of fibrosis stages 2 and 3 or higher[17]

		Cutoff value	PPV	NPV	Sensitivity	Specificity	FN	FP
FIB-4 index	Low	1.30	0.257	0.962	0.892	0.513	0.108	0.487
	High	2.67	0.382	0.093	0.547	0.833	0.453	0.167
COL4-7S (ng/mL), F0-1 vs F2-4)	Low	3.8	0.541	0.842	0.902	0.405	0.098	0.595
	High	6.0	0.775	0.676	0.446	0.900	0.554	0.100
FIB-4 and COL4-7S		1.3 and 3.8	0.690	0.792	0.752	0.737	0.248	0.263
COL4-7S, F0-2 vs F3-4	Low	4.8	0.315	0.969	0.892	0.634	0.108	0.366
	High	6.8	0.530	0.081	0.576	0.904	0.424	0.096
FIB-4 and COL4-7S (ng/mL)		1.3 and 4.8	0.366	0.953	0.806	0.737	0.194	0.263
F0-1 vs F2-4		1.3 and 4.3	0.706	0.787	0.730	0.766	0.270	0.234
F0-2 vs F3-4		1.3 and 4.3	0.307	0.963	0.871	0.630	0.129	0.370

Cutoff values were calculated with 90% sensitivity and 90% specificity. Type IV collagen 7S scores were measured using the radioimmunoassay method. FIB-4: Fibrosis-4; COL4-7S: Type IV collagen 7S; PPV: Positive predictive value; NPV: Negative predictive value; FN: False negative rate; FP: False positive rate.