Table 3 Measurement tools for social frailty (Based on social needs fulfilment Theory)

Theoretical framework: Social Needs Fulfilment (SNF) theory

The Makizako Social Frailty Index of 5 items

3 dimensions (5 items)

1. Daily social activity (1 item)

2. Social role (1 item)

3. Social relationships (3 items)

The score was the sum of 5 items (range 0–5)

Binary rating on each item (yes/no)

0 indicates non-social frailty

1 indicates pre-social frailty

≥ 2 indicates social frailty

Makizako, 2015 (Japan) [8]

7-item social frailty index (SFI)

2 dimensions (7 items)

1. General/social resources (4 items)

2. Social behaviors and activities (3 items)

The score is the sum of 7 items (range 0–7)

Binary rating on each item

1 = yes/present

0 = no/absent

0 indicates no social frailty

1 indicates low social frailty

≥ 2 indicates social frailty

Teo, 2017 (Singapore) [17]

HALFT scale

5 items

1. Help others (Social role) (1 item)

2. Participation (Social activity) (1 item)

3. Loneliness (1 item)

4. Financial (Socio-economic status) (1 item)

5. Talk (Social relationships) (1 item)

The score is the sum of 5 items (range 0–5)

Binary rating on each item (yes/no)

0 indicates non-social frailty

1–2 indicate pre-social frailty

≥ 3 indicates social frailty

Ma, 2018 (China) [5]

4-item social frailty screening index

4 items

1. General resources (1 item)

2. Social resources (1 item)

3. Social behavior (1 item)

4. Fulfillment of basic social needs (1 item)

The score is the sum of 4 items. (range 0–4)

Items 1, 3, and 4 are 4-point Likert scale

4 = very satisfied

3 = satisfied

2 = dissatisfied

1 = very dissatisfied (“very dissatisfied” assign a score of 1)

Item 2 is answered by binary rating.

1 = yes

0 = no

0 indicates socially robust

1 indicates pre-social frailty

≥ 2 indicates social frailty

Yamada, 2018 (Japan) [6]

Social frailty scale(SFS)

5 items from (Makizako, 2015)

1. Neighborhood meeting attendance

2. Talking to friend(s)

3. Someone gives you love and affection

4. Living alone

5. Meeting someone every day

The score is the sum of 4 items. (range 0–5)

The answer of “yes” to the item 4 and “no” to the items 1,2,3,5 were considered as 1 score.

0 indicates non-social frailty

1–2 indicate pre-social frailty

≥ 3 indicates social frailty

Yoo, 2019 (Korea) [25]

8-item social frailty scale (SFS-8)

3 dimensions (8 items)

1. Social resources (3 items)

2. Social activities and financial resources (3 items)

3. Social need fulfillment (2 items)

The score is the sum of 8 items. (range 0–8)

Binary rating on each item (yes/no)

0–1 indicates non-social frailty

2–3 indicate pre-social frailty

≥ 4 indicates social frailty

Pek, 2020 (Singapore) [26]

6-item social frailty scale (SFS-6)

4 dimensions (6 items)

1. Social support (2 items)

2. Social isolation (2 items)

3. Social activity (1 item)

4. Economic status (1 item)

The score is the sum of 6 items. (range 0–6)

Binary rating on each item (yes/no)

1- point for a negative response

0–1 indicates non-social frailty

2–3 indicate pre-social frailty

≥ 4 indicates social frailty

Chen, 2021 (China) [18]

Social Frailty Index (SFI)

5 dimensions(17items)

1. Decision making participation (5 items)

2. Social network(friends)(3items)

3. Social activity(4items)

4. Social network(others)(2items)

5. Social activity at community level (3 items)

The indicator was coded in binary (1 = Yes and 0 = No) or quintile form (Daily/several times a week = 1; Once a week/several times a month = 0.75; At least once a month = 0.50; Rarely in a year = 0.25; never/not relevant = 0 ) then standardizing their responses on a scale of 0 to 100. (sum of all indicators and further harmonized into range 0–100)

A higher score indicates a high level of social frailty.

Irshad, 2024, (India) [27]