The role of medication adherence in the association between depressive symptoms and quality of life in older adults with type 2 diabetes mellitus

BACKGROUND: At present, the role of medication adherence in the association between depressive symptoms and quality of life (QOL) in older adults with type 2 diabetes mellitus (T2DM) was unclear. The purpose of this study was to explore the associations among depressive symptoms, medication adherence and QOL in older adults with T2DM. METHODS: In this cross-sectional study, 300 older adults with T2DM from the First Affiliated Hospital of Anhui Medical University were enrolled. Among them, 115 patients had depressive symptoms and 185 had no depressive symptoms. Univariate linear regression analysis was conducted to identify possible covariates. Univariate and multivariable linear regression analyses were performed to explore the associations between depressive symptoms and medication adherence or QOL in older adults with T2DM. Multiplicative interaction analysis was evaluated whether there was interaction effect between medication adherence and depressive symptoms on QOL of patients. Mediating effect analysis was used to analyze the medication effect of medication adherence on depressive symptoms and QOL in older adults with T2DM. RESULTS: Decreased medication adherence was observed in patients with depressive symptoms (β = -0.67, 95%CI: -1.10, -0.24) after adjusting for covariates. Depressive symptoms were associated with decreased QOL in older adults with T2DM (β = -5.99, 95%CI: -7.56, -4.42). The mediating analysis revealed that depressive symptoms were associated with decreased medication adherence (β = -0.67, 95%CI: -1.09, -0.25). Medication adherence was linked with increased QOL of older adults with T2DM (β = 0.65, 95%CI: 0.24, 1.06). Depressive symptoms were correlated with decreased QOL of older adults with T2DM (β = -5.56, 95%CI: -7.10, -4.01). The percentage mediated by medication adherence on depressive symptoms and QOL in older adults with T2DM was 10.61%. CONCLUSION: Medication adherence might mediate depressive symptoms and QOL of older adults with T2DM, which might provide a reference for the improvement of QOL of these patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-023-03929-8.