Background: Mounting evidence of loneliness and negative health impacts has placed loneliness among the "geriatric giants" in need of intervention by the healthcare system.

Objective: To evaluate the literature regarding the health impact of loneliness among older adults living in congregate living settings (i.e., assisted living, nursing homes).

Materials and methods: Five databases were searched for quantitative and qualitative studies from January 1990 through August 2021. Methodological quality was assessed using modified criteria specific to quantitative and qualitative studies. Dual review assured the quality of the systematic review conduct.

Results: Five qualitative, 3 mixed method, 19 cross-sectional, and 4 cohort articles were eligible. Despite different tools used to measure loneliness, loneliness appeared common among older residents in congregate living situations. In most studies, loneliness was associated with depression (regardless of scale used), albeit all but one came from cross-sectional studies. Few studies noted the association between loneliness and suicidal ideation and frailty. The three cohort studies that evaluated loneliness and mortality had mixed results. Resilience and activities appeared to mediate the association between loneliness and negative health outcomes and social support appeared to moderate associations.

Conclusions: For older adults living in congregate long term care settings, loneliness is a common phenomenon, with cross-sectional studies suggesting links to depression, suicidal ideation, and frailty. Additional longitudinal studies to understand the impact of loneliness on health outcomes in older adults living in congregate settings are needed, as are rigorous evidence-based interventions to address loneliness and mitigate its harmful effects during life's final chapter.