Prevalence, combination patterns, and quality of life factors of multimorbidity among older adults in southern China based on the health ecological model.

Multimorbidity is increasingly prevalent among older adults and poses significant challenges to health and well-being. This study applied a health ecological model to investigate the prevalence, determinants, and common disease patterns of multimorbidity, as well as the factors associated with quality of life (QoL) among older adults in southern China. A cross-sectional survey was conducted among 2404 individuals aged 60 years and older using a multi-stage random sampling method. Quality of life was assessed using the EQ-5D-5L scale. Multimorbidity was defined as the presence of two or more chronic conditions. The Apriori algorithm identified common multimorbidity combinations. Factors influencing multimorbidity were analysed using univariate and multivariate logistic regression based on a health ecological model. Tobit regression was used to assess associated factors of QoL among patients with multimorbidity. The prevalence of multimorbidity was 44.3%. Hypertension featured prominently in disease clusters, with 'hypertension + hyperlipidemia' as the top two-disease combination. Risk factors for multimorbidity included QoL, age, body mass index (BMI), exercise, sleep quality, social participation, education level, per capita monthly household income, and region. The number of chronic diseases was negatively associated with QoL. Factors significantly influencing QoL included age(≥80, β = -0.087, P < 0.001), number of chronic diseases(>3 diseases, β = -0.029, P = 0.012), fresh fruit intake (occasionally: β = 0.052; often: β = 0.064, all P < 0.005), dietary balance (always: β = 0.078, P = 0.007), exercise frequency (1-3 days: β = -0.039; >3 days: β = 0.024, all P < 0.005), sleep quality (better: β = -0.034; worse: β = -0.070; very bad: β = -0.161; all P < 0.005), social participation (β = 0.034; P = 0.006), education level (primary school: β = 0.028, P = 0.028; college/higher vocational school: β = 0.083, P = 0.010), and region (western: β = 0.083; northern: β = 0.064; eastern: β = 0.132; all P < 0.001). Multimorbidity among older adults in southern China is associated with demographic, behavioral, interpersonal, socioeconomic, and regional factors. Therefore, it is recommended to implement differentiated insurance reimbursement, reinforce county-level resource allocation, integrate community services via the World Health Organization's (WHO) Integrated Care for Older People (ICOPE) framework, and promote individual lifestyle measures. Given the reliance on self-reported cross-sectional data, the findings are constrained by limited causal inference and possible recall bias. Longitudinal studies are needed to validate and refine the conclusions.