Table 1 Theoretical frameworks related to social frailty

Deficit accumulation model

The proportion of accumulated deficits (e.g., symptoms, signs, functional impairments, and laboratory abnormalities) measured by index values can represent an individual’s state at the time of their health assessment.

1. Frailty index

2. Social frailty phenotype

3. Social vulnerability index

Mitnitski, 2001, (Canada) [22]

Social Production Function (SPF) theory

SPF theory specifies three distinctive social needs, which are associated with individual’s well-being.

1. The need for affection

2. Behavioral confirmation

3. Status

None

Steverink, 2006, (Netherlands) [23]

Social Ecology Theory (SET)

SV can be considered at various levels of influence from individual to close family, wider network, and societal context.

Seven dimensions of SV based on a SET were proposed as follows:

None

Andrew, 2014, (Canada) [16]

SV dimensions

SET framework

1. Self-esteem

2. Sense of control

Individual level

3. Living situation

4. Relations with others

Interpersonal level

5. Engagement

6. Social Support

Community level

7. Contextual socio-economic status

Society level

Social Needs Fulfilment (SNF) theory

SNF can be defined as “a continuum of being at risk of losing, or having lost, social and general resources, activities, or abilities that are important for fulfilling one or more basic social needs during the life span.”

SNF employed a theory of needs, goals, and resources based on SPF theory as a heuristic for ordering and structuring SV in four dimensions as follows:

1. Social needs

2. General resources

3. Social fulfilment

4. Self-management

1. The Makizako Social Frailty Index of 5 items

2. The HALFT scale

3. 4-item social frailty screening index

4. 7-item social frailty index

5. 8-item and 6-item social frailty scale (SFS-8 and SFS-6)

6. Social Frailty

Index (SFI)

7. Social Frailty

Index (SFI)

Bunt, 2017, (Netherlands) [3]