Multimorbidity, Depressive Symptoms, and Their Associations with Frailty and Quality of Life in Community-Dwelling Older Adults

Multimorbidity and frailty are common among older adults, and they have been linked with negative physical and psychological consequences. This study looked at the direct and indirect relationships between multiple long-term conditions (MLTC), frailty, and quality of life (QoL), as well as the impact of depressive symptoms as a mediator among Saudi community-dwelling adults. Methods: This cross-sectional study included 182 community-dwelling people aged ≥60 years from the Riyadh region. Multimorbidity was defined as the presence of two or more chronic illnesses. Frailty was measured using the Tilburg Frailty Indicator (TFI), depressive symptoms with the Geriatric Depression Scale (GDS-15), and quality of life with the SF-12 (Physical [PCS] and Mental [MCS] Component Summary scores). Path analysis with robust maximum likelihood estimation was used to investigate direct and indirect relationships. Sex and age-stratified analyses were carried out. Results: Having more chronic illnesses was linked to increased depressive symptoms (β = 0.29, p < 0.001) and frailty (β = 0.30, p < 0.001). Depressive symptoms were significantly associated with frailty (β = 0.56, p < 0.001) and largely moderated the association between multimorbidity and frailty (indirect β = 0.16, 95% CI: 0.11-0.36). Multimorbidity was also related to lower physical QoL, both directly and indirectly via depressive symptoms, but no significant relationships were found for mental QoL. The structural connections were consistent across sex and age groups. Higher frailty ratings independently predicted falls in the past 12 months. Conclusions: Multimorbidity is related to higher frailty and worse physical quality of life among community-dwelling older individuals, with depressive symptoms serving as a partial mediator. These findings emphasize the need to include mental health assessments in chronic illness and frailty care to maintain physical function and avoid negative outcomes in aging populations.