Bolle 2015
Reason for exclusion	Evidence/aim (not to reduce social isolation or loneliness)
Burkow 2015
Reason for exclusion	Target population (included <60 years old, and not disaggregated by age)
Clarkson 2018
Reason for exclusion	Evidence/aim (not to reduce social isolation or loneliness)
Cooper 2014
Reason for exclusion	Target population (included <60 years old, and not disaggregated by age)
Dam 2017
Reason for exclusion	Target population (included <60 years old, and not disaggregated by age)
Dickens 2011
Reason for exclusion	Intervention (not digital)
Erfani 2018
Reason for exclusion	Target population (included <60 years old, and not disaggregated by age)
Fan 2016
Reason for exclusion	Study design (not a systematic review of effectiveness)
Forsman 2017
Reason for exclusion	Study design (not a systematic review of effectiveness)
Gine‐Garriga 2017
Reason for exclusion	Intervention (not digital)
Gorenko 2021
Reason for exclusion	Study design (not a systematic review of effectiveness)
Jones 2019
Reason for exclusion	Intervention (not digital)
Lara 2016
Reason for exclusion	Target population (included <60 years old, and not disaggregated by age)
Nicholson 2012
Reason for exclusion	Intervention (not digital)
Nijman 2019
Reason for exclusion	Target population (included <60 years old, and not disaggregated by age)
Perkins 2012
Reason for exclusion	Study design (not a non‐comparative primary study)
Preston 2019
Reason for exclusion	Study design (not a non‐comparative primary study)
Rebollar 2015
Reason for exclusion	Study design (not a non‐comparative primary study)
Selak 2019
Reason for exclusion	Study design (not a systematic review of effectiveness)
Sumner 2021
Reason for exclusion	Evidence/aim (not to reduce social isolation or loneliness)
Toh 2016
Reason for exclusion	Intervention (not digital)
Winterton 2011
Reason for exclusion	Study design (not a non‐comparative primary study)
Zeppegno 2018
Reason for exclusion	Intervention (not digital)