Contribution of depression and cardiometabolic diseases and the role of depression treatment in survival and functioning in older adults

Background: Achieving survival free from physical disability or neurocognitive impairment, known as disability-free survival (DFS), is a key public health goal. This study aimed to (1) determine the long-term interactive effects of depression and cardiometabolic diseases (CMDs) on DFS, and (2) explore any associated antidepressant treatment effect on improvements in DFS among older adults. Methods: We used data from the ASPREE trial and its observational follow-ups (2010-2019), involving community-dwelling adults aged ≥ 70 years (≥65 for U.S. minorities). Time-updated Cox models were used to estimate the combined effect of depression and CMDs (type 2 diabetes, dyslipidemia, hypertension, chronic kidney disease, metabolic-associated steatotic liver disease, and major adverse cardiovascular events) as well as cardiometabolic multimorbidity (≥2 CMDs) on DFS. To evaluate the improvement in DFS associated with antidepressant treatment in individuals with depression, we estimated the number needed to treat (NNT) to achieve a one-year increase in DFS through antidepressant therapy. Findings: 18,739 participants (mean [SD] age, 75.1 [4.6] years; 56.0% female) were included, with a median follow-up of seven years; individuals with both depression and CMDs demonstrated a significantly lower DFS compared to those without either condition. In individuals with depressive symptoms, antidepressant use was associated with a median increase in DFS of 2.95 years (95% CI, 2.12-3.04), with an estimated NNT of 8.05 (95% CI, 5.63-14.86) associated with a one-year increase in DFS. Interpretation: Integrating depression treatment into chronic disease management, when appropriate, is associated with an improvement in DFS among older adults. Funding: Deakin University Postgraduate Research Scholarship.