Effects of Combined Physical and Cognitive Interventions on Older Adults With Dementia: A Systematic Review and Meta-Analysis

OBJECTIVES: Physical and cognitive interventions provide benefits to persons with dementia (PwD); however, the evidence on the effects of combined physical and cognitive interventions on PwD remains inconsistent. This review aimed to synthesize existing evidence and compare the effects of combined interventions with those of each intervention alone on cognitive, physical, psychological, functional, and health-related quality of life (HRQoL) outcomes for PwD. DESIGN: Systematic review and meta-analysis. SETTING AND PARTICIPANTS: Older adults with dementia. METHODS: Searches were conducted across 8 English and Chinese databases from their inception dates to September 10, 2024. Quality appraisal was performed using Cochrane's risk of bias tool. Random-effects models were used for meta-analysis, and subgroup analyses and meta-regression were applied to explore potential moderators. RESULTS: A total of 23 studies involving 1716 participants were included. Combined interventions significantly improved global cognition [standardized mean difference (SMD), 0.65; 95% CI, 0.35-0.95; P < .001], processing speed (SMD, 0.33; 95% CI, 0.03-0.63; P = .03), functional mobility (SMD, 0.85; 95% CI, 0.18-1.53; P = .01), strength (SMD, 0.95; 95% CI, 0.28-1.61; P = .005), depression (SMD, -1.04; 95% CI, -1.73 to -0.36; P = .003), and HRQoL (SMD, 0.71; 95% CI, 0.24-1.18; P = .003) compared with active or passive controls. Combined interventions did not provide better overall benefits than using either intervention alone. Further analysis showed that the effectiveness of combined interventions on global cognition depended on the age of PwD. CONCLUSIONS AND IMPLICATIONS: Combined interventions are effective in improving cognitive, physical, psychological, and HRQoL outcomes in PwD. They should be integrated into dementia management protocols. Future research should focus on multiarm randomized controlled trials with long-term follow-up to directly compare the effects of combined interventions with those of single interventions and explore their long-term sustainability.