. 2022 Sep 14;12(10):e062951. doi: 10.1136/bmjopen-2022-062951

Table 1.

Summary of characteristics of included studies

Study ID	Participants	Intervention	Outcomes
Randomised trials
Clarke et al 1992 Community, UK²⁵	523 adults over 75 years living alone Age, gender not reported	Referral: Recruited via mail invitation Link worker: Lay community-based health worker, training and experience not specified. Contacts: Minimum 3 home visits with tailored support Duration: 2 years Comparator: Usual care	Primary outcome: Survival Secondary outcomes: Activities of daily living Information/orientation score Loneliness Morale Self-rated health Social contacts Primary healthcare utilisation Costs: None reported Data collection: 0, 24 months. Survival assessed at 6-monthly intervals from baseline to 3.5 years
Grant et al 2000 Community, UK²⁶	152 adults over 16 who GP felt would benefit from intervention Mean age 43.2 years, 75% female.	Referral: Recruited via GP referral Link worker: Lay ‘referral facilitator’ trained and employed by a community organisation. Based in community Contacts: 1 face-to-face assessment within a week of referral. Average of 1.7 telephone or face-to-face contacts reported Duration: 1 month Comparator: Usual care	Primary outcomes: Mental health: depression and anxiety Social support Secondary outcomes: Quality of life Functional health Primary healthcare utilisation including medications and referrals Costs: Intervention Primary healthcare utilisation Referrals to other agencies Data collection: 0, 1, 4 months
Heisler et al 2022 Community, USA²⁹	3159 adults aged <65 years residing in a low-income zip code with >3 ED visits or one ambulatory care sensitive admission in last year Mean age 29 years, 64% female.	Referral: Recruited via Medicaid Link worker: Community health workers, familiar with zip code, trained and employed by community organisations Contacts: 55% at least one contact, mean of 1.9 contacts Duration: Tailored, but up to 1 year Comparator: Usual care	Primary outcomes: Healthcare utilisations including Ambulatory care visits ED visits Hospital admissions Costs: Healthcare utilisation costs Data collection: 12 months pre-and post-randomisation
Kangovi et al 2018 Primary care, USA²⁸	592 adults attending three primary care clinics, who resided in a high-poverty zip code had a diagnosis for two or more chronic diseases Mean age 52.6 years, 62.5% female.	Referral: Recruited via primary care clinics (PCPs) Link worker: Community health workers, with high school diploma. 1 month training in motivational interviewing, action planning and on the job. Based in PCPs Contacts: Monthly face-to-face meetings and weekly telephone check-ins. Duration: 6 months Comparator: Chronic disease goal setting with PCP only	Primary outcome: HRQoL, physical health component (SF-12-V2 PCS) Secondary outcomes: HRQoL, mental health component (SF-12-V2 MCS) Patient activation Chronic disease control (BP, HbA1C, BMI or CPD) Patient-reported quality of primary care All cause hospitalisations Costs: None reported Data collection: 0, 6, 9 months
Kangovi et al 2017 Community, USA²⁷	302 adults attending GIM clinics, living in deprived area, and were diagnosed with two or more chronic diseases Mean age 56 years, 74% female.	Referral: Recruited via PCPs Link worker: Community health workers, with high school diploma. 1 month training in motivational interviewing, action planning and on the job. Based in PCPs Contacts: Monthly face-to-face meetings and weekly telephone check ins. Duration: 6 months Comparator: Chronic disease goal setting with PCP only	Primary outcome: Change in chronic disease control (HbA1C, BMI, BP, or CPD) Secondary outcomes: Achievement of chronic disease management goals HRQoL (SF-12-V2 PCS and MCS) Patient activation Patient-reported quality of primary care All cause hospitalisations Costs: Return-on-investment analysis reported on cost savings related to reduced hospitalisations³³ Data collection: 0, 6 months for PROMs. 6 and 12 months for hospitalisations
Controlled before–after studies
Carnes et al 2017 Primary care, UK³²	480 adults frequently attending primary care, who presented with social isolation or mild mental health problems. Median age 56 years, 59% female.	Referral: GP referral Link worker: 3 lay ‘social prescribing coordinators’ (SPC) trained in social work and managed by community organisation. Based across 22 GP practices. Additional support from volunteers available Contacts: Initial 1 hour meeting and up to six sessions with the SPC, unlimited volunteer support Duration: 6 months Comparator: Propensity matched controls drawn from GP practices in nearby areas with no social prescribing service	Primary outcome: Not specified Secondary outcomes: Self-rated health Mental health: depression and anxiety Well-being Positive and active engagement in life Number of regular activities A&E visits in past 3 months Annual GP consultation rate Number of medications in previous 6 months Costs: None reported Data collection: 0, 8 months
Dickens et al 2011 Community, UK³⁰	392 adults over 50 years attending primary care at risk of social isolation Mean age 71 years, 62% male.	Referral: GP referral Link worker: Mentors often with teaching or creative skills, managed by a community organisation. Training not described. Based in community Contacts: Face-to-face meetings, frequency not specified Duration: 3 months Comparator: Matched controls from a sample drawn from 3 GP practices in nearby areas with no mentoring service	Primary outcome: HRQoL, mental health component (SF-12-V2 MCS) Secondary outcomes: HRQoL, physical health component (SF-12-V2 PCS) HRQoL (EQ-5D-3L) Mental health: depression Social activities Social support Social participation Costs: None reported Data collection: 0, 3 months
Mercer et al 2019 Primary care, UK³¹	900 adults attending primary care in most deprived areas of Glasgow deemed suitable for intervention by GP Median age 49 years, 60% female.	Referral: GP referral Link worker: Community links practitioners with prior experience of community work, managed by a community organisation. 1 month training on role, supporting clients, engaging practices and mapping resources. Based in GP practices Contacts: Face-to-face meetings. Average of 3 meetings reported Duration: 9 months Comparator: Sample drawn from 6 GP practices in Glasgow without a community links practitioner	Primary outcome: HRQoL (EQ-5D-5L) Secondary outcomes: Well-being Mental health: depression and anxiety Work and social adjustment scale Self-reported lifestyle behaviours (smoking, alcohol, exercise) Costs: None reported Data collection: 0, 9 months

A&E, Accident and Emergency; A&E, accident and emergency; BMI, body mass index; BP, blood pressure; CPD, chronic pulmonary disease; ED, Emergency Department; ED, emergency department; GIM, author to define; GIM, General Internal Medicine; GP, general practitioner; GP, General Practice; HbA1C, glycated haemoglobin; HRQoL, health-related quality of life; PCP, primary care practice; PROM, patient-reported outcome measure; SPC, social prescribing coordinator.