Clinical significance and pathogenic mechanisms of fatigue in metabolic dysfunction-associated steatotic liver disease

Table 2 Key instruments used to diagnose and evaluate fatigue severity, including those applicable to patients with chronic liver disease

Ref.	Scale	Domains assessed	Type of assessment	Time lag	Reliability (Cronbach's α)	Strengths and limitations	Most commonly used in	Use for fatigue assessment in chronic liver disease
[49,50]	Fatigue Assessment Scale	Severity, physical and mental fatigue	10 items (5 physical fatigue, 5 mental fatigue); 5-point Likert scale; total score 10-50; ≥ 22 indicates clinically significant fatigue	How a person usually feels	0.90	Differentiates between depression and fatigue; available in 20 languages	General population; used in 26 diseases/conditions including stroke, neurologic disorders, rheumatoid arthritis, idiopathic pulmonary fibrosis; frequently used in sarcoidosis	MASLD
[51]	Fatigue Impact Scale	Cognitive, physical, emotional components of fatigue	40 items; 5-point Likert scale; higher scores indicate more severe fatigue	Past month	0.87; test–retest reliability r = 0.71-0.83	Adapted and validated in 30 languages and many patient groups	General population; wide range of conditions including infectious diseases; target populations: Neurological disorders	PBC; chronic hepatitis B and C
[52-54]	Fatigue Severity Scale	Severity and impact of fatigue on activities and lifestyle	9 items; 7-point Likert scale; total score is mean of items; Fatigue Severity Scale ≥ 4 indicates clinically significant fatigue	Past week	0.93-0.95; high test-retest reliability	Good psychometric performance; cannot differentiate central vs peripheral fatigue; difficulty identifying peripheral fatigue especially muscle dysfunction	General population; wide range of conditions; target populations: Neurological and rheumatological disorders	Chronic hepatitis C; liver cirrhosis
[55-57]	Functional Assessment of Chronic Illness Therapy-Fatigue	Physical, social/family, emotional, functional well-being, fatigue	13 items; 5-point Likert scale; higher scores mean less fatigue	Past week	0.95; good internal consistency and convergent validity	Validated internationally; scores comparable to population norms; requires permission for use	General population; target populations: Cancer patients	Chronic hepatitis C, chronic hepatitis B, MASLD
[58-60]	Multidimensional fatigue inventory	Five subscales: General fatigue, physical fatigue, decreased activity, reduced motivation, mental fatigue	20 items; 5-point Likert scale; total score sum of subscales (20-100); higher scores indicate more severe fatigue	Previous days	0.83-0.94; test-retest reliability r = 0.76	Focuses on cognitive appraisal rather than objective fatigue impact; classification of fatigue subscales is debatable	General population; wide range of conditions	MASLD
[61,62]	Visual analogue scale of fatigue	Energy, fatigue	10 cm line from zero (no fatigue) to extreme fatigue; patient marks current fatigue level	Current level	0.94-0.96; strongly correlated with PHQ-9 total score (r = 0.61) and individual items (r = 0.19-0.67)	Validated in adults 18-55 years; poor differentiation between fatigue and drowsiness; patients may hesitate to use extreme scale values	General population	Chronic hepatitis C, chronic hepatitis B, MASLD, PBC, autoimmune hepatitis, nodular regenerative hyperplasia, liver cirrhosis

MASLD: Metabolic dysfunction-associated steatotic liver disease; PBC: Primary biliary cholangitis; PHQ-9: Patient Health Questionnaire-9.