Table 1.

List of assessment items for social frailty status

Study	Subject	Assessment domains	Criteria	Outcome
Gobbens et al., 20109)	484 Community-dwelling persons (aged≥75 years)	Social frailty consists of three components in the Tilburg Frailty Indicator	Continuous variable with higher scores indicating higher levels of social frailty	Associated factors
Gobbens et al., 201411)	1,154 Community-dwelling older adults (aged ≥75 years)	(1) living alone		QoL
Gobbens et al., 201712)	671 Older adults (aged ≥70 years)	(2) lack of social relations		QoL
Takabayashi et al., 201713)	647 Older adults with heart failure	(3) lack of social support		Risk of social frailty
Makizako et al., 20154)	4,304 Older adults living in the community (aged ≥65 years)	Self-reported questionnaire including 5 domains	0, robust; 1, social prefrailty; 2 to 5, social frailty	Disability incidence
		(1) going out less frequently
		(2) rarely visiting friends
Tsutsumimoto et al., 201721)	4,425 Japanese older adults (aged≥65 years)	(3) feeling unhelpful to friends or family		Cognitive and physical deficits
		(4) livinga lone
		(5) not talking to someone every day
Garre-Olmo et al., 201315)	1,245 Older adults (aged ≥75 years)	(1) Living alone	2 or more	Mortality
		(2) Lack of a person to help with ADL
		(3) Infrequent contact with family (less than once a week)
		(4) Infrequent contact with friends or neighbors (less than once a week)
		(5) Absence of a confidant
		(6) Lack of support for daily living during the past 3 months
Teo et al., 201714)	2,406 Chinese adults (aged ≥55 years)	Seven-item social frailty index	0, nil social frailty; 1, low social frailty; 2 to 7, high social frailty	IADL dependency
		(1) Living alone		Severe dependency
		(2) No education
		(3) Absence of a confidant
		(4) Infrequent contact
		(5) Infrequent social activities
		(6) Financial difficulty
		(7) Socioeconomic deprivation
Bunt et al., 201716)	28 Community-dwelling elderly people	Social Vulnerability Index Dutch version	Continuous variable	Validity
		(1) Communication to engage in wider community
		(2) Living situation
		(3) Social support
		(4) Socially oriented activities of daily living
		(5) Leisure activities
		(6) Ryff scale
		(7) How do you feel about your life
		(8) Socioeconomic status

QoL, quality of life; ADL, activities of daily living; IADL, instrumental ADL.