Abstract
BACKGROUND: The global aging crisis has intensified concerns about disability, frailty, anxiety, and depression in older adults, particularly those with multimorbidity. However, the interrelationships among these factors remain not fully understood. This study investigates the mediating role of frailty between disability and anxiety/depression in this population. METHODS: A cross-sectional study was conducted from October 2022 to January 2023, enrolling 4,372 older adults with multimorbidity from 3 tertiary hospitals, 5 secondary hospitals, and 3 community health centers in Zunyi, China. Data were collected using validated instruments: Activities of Daily Living (ADL), the Self-Rating Anxiety Scale (SAS), Generalized Anxiety Disorder-7 (GAD-7), Geriatric Depression Scale-Short Form (GDS-15), and Frailty Phenotype. Spearman correlation, binary logistic regression, and mediation analysis (SPSS PROCESS 3.5) with Bootstrap testing (5,000 resamples) were employed. RESULTS: Among participants, 437 (10.0%) exhibited disability. Significant correlations were observed between disability and anxiety/depression (r = 0.32-0.41, p < 0.001). Frailty partially mediated the disability-anxiety (50.45% of total effect) and disability-depression (48.17%) relationships (p < 0.001). CONCLUSION: Frailty serves as a critical mediator between disability, anxiety and depression in older adults with chronic disease comorbidity. Targeted interventions addressing disability and frailty may significantly mitigate anxiety and depression, thereby improving mental health and quality of life in this vulnerable population.