Pain and depression mediate the relationship between multimorbidity and frailty in older adults with diabetes

Frailty is increasingly recognized as a significant risk factor for death and disability in older adults with diabetes. Although previous studies have confirmed the correlation between the number of comorbid chronic conditions and frailty in older adults with diabetes, the mechanism underlying this effect remains unclear. Pain and depression are common symptoms accompanying diabetes. Therefore, this study aims to examine the mediation effect of pain and depression on the relationship between multimorbidity and frailty in older adults with diabetes. This study used data from the China Health and Retirement Longitudinal Study conducted by Peking University in 2018 and 2020, selecting 799 older adults with diabetes. Descriptive and correlation analyses were performed using SPSS 27.0, and the mediation analyses were conducted using the PROCESS macro. Pain and depression played mediating roles between multimorbidity and frailty in older adults with diabetes, with direct (0.062) and indirect (0.075) effects accounting for 45.26% and 54.74% of the total effect (0.137), respectively. Further analysis revealed three significant indirect pathways: (1) multimorbidity → pain → frailty (8.03% of the total effect), (2) multimorbidity → depression → frailty (43.07%), and (3) multimorbidity → pain → depression → frailty (3.65%). These findings highlight the importance of early intervention for older adults with diabetes who have chronic diseases, particularly those experiencing pain and depression. However, the generalizability of these findings may be limited to community-dwelling older adults, and further validation in hospitalized or institutionalized populations is warranted.