Background: community-based complex interventions for older adults have a variety of names, including Comprehensive Geriatric Assessment, but often share core components such as holistic needs assessment and care planning.

Objective: to summarise evidence for the components and effectiveness of community-based complex interventions for improving older adults' independent living and quality of life (QoL).

Methods: we searched nine databases and trial registries to February 2022 for randomised controlled trials comparing complex interventions to usual care. Primary outcomes included living at home and QoL. Secondary outcomes included mortality, hospitalisation, institutionalisation, cognitive function and functional status. We pooled data using risk ratios (RRs) or standardised mean differences (SMDs) with 95% confidence intervals (CIs).

Results: we included 50 trials of mostly moderate quality. Most reported using holistic assessment (94%) and care planning (90%). Twenty-seven (54%) involved multidisciplinary care, with 29.6% delivered mainly by primary care teams without geriatricians. Nurses were the most frequent care coordinators. Complex interventions increased the likelihood of living at home (RR 1.05; 95% CI 1.00-1.10; moderate-quality evidence) but did not affect QoL. Supported by high-quality evidence, they reduced mortality (RR 0.86; 95% CI 0.77-0.96), enhanced cognitive function (SMD 0.12; 95% CI 0.02-0.22) and improved instrumental activities of daily living (ADLs) (SMD 0.11; 95% CI 0.01-0.21) and combined basic/instrumental ADLs (SMD 0.08; 95% CI 0.03-0.13).

Conclusions: complex interventions involving holistic assessment and care planning increased the chance of living at home, reduced mortality and improved cognitive function and some ADLs.