Health-related quality of life mediates associations between multi-morbidity and depressive symptoms in Chinese primary care patients

BACKGROUND Qualifying the relationship between multi-morbidity, health-related quality of life (HRQOL) and depressive symptoms in primary care can help to inform the development of appropriate interventions and services which can help to enhance HRQOL in patients with chronic disease. OBJECTIVE The objective of this study was to determine whether the physical aspect of HRQOL mediates the relationship between chronic disease multi-morbidity and depressive symptoms in Chinese primary care patients. METHODS A cross-sectional survey was conducted on patients recruited from the waiting rooms of 59 primary care clinics distributed across Hong Kong. About 9259 subjects were included for the mediation model analysis. The primary outcome was level of depressive symptoms as measured by the Patient Health Questionniare 9. The mediation model was tested using a bootstrapping method. RESULTS The prevalence of chronic disease was 50.4%, with 25.4% having two or more co-morbidities. The relationship between multi-morbidity and depressive symptoms was found to be mediated by the Physical Component Summary score of the SF-12 v2. Further analysis found the general health (GH) and role physical domains of the SF-12 were the strongest mediators, followed by bodily pain and physical functioning (PF). CONCLUSION To enhance the functional capacity of primary care patients with co-existing chronic disease and depressive symptoms, health care interventions should be directed at improving the physical aspects of HRQOL, in particular enhancing patients' GH perception, role functioning and PF, and to better manage chronic pain.