Association between cardiovascular-kidney-metabolic syndromeand depressive symptoms in middle-aged and older Chineseadults: a cross-sectional and longitudinal analysis

Background: Cardiovascular-Kidney-Metabolic (CKM) syndrome and depressive disorder represent major public health burdens. While associations between depression and individual components of CKM syndrome have been established, the relationship between depression and CKM syndrome as an integrated clinical construct remains poorly understood. Methods: Data from the China Health and Retirement Longitudinal Study (CHARLS) were used, including 8,088 participants in cross-sectional analyses and 1,803 in longitudinal analyses. CKM syndrome was classified according to the American Heart Association (AHA) staging criteria, and depressive symptoms were assessed using the 10-item Center for Epidemiologic Studies Depression Scale (CES-D-10). The association between CKM stage and depressive symptoms was evaluated using ordinary least squares regression models with five levels of covariate adjustment. Subgroup analyses and interaction tests were conducted to investigate interaction effects across different populations. Results: Higher CKM stages were significantly associated with increased depressive symptom severity. In the cross-sectional analysis (2011), mean CES-D-10 scores were 8.6 ± 6.4, 8.6 ± 6.3, 8.1 ± 6.2, and 10.7 ± 6.9 for the total population and CKM stages 0–1, 2–3, and 4, respectively. Scores in stage 4 exceeded the threshold for severe depressive symptoms and were significantly higher than those in other stages (P < 0.001). Subgroup analyses further confirmed the robustness of cross-sectional findings. In longitudinal analyses, progression in CKM stage over a four-year period was independently associated with an increase in CES-D-10 scores (β = 0.31, 95% CI: fully adjusted model). Conclusions: CKM syndrome is significantly associated with depressive symptoms, especially in stage 4. There is a positive relationship between CKM progression and depressive symptom severity, highlighting the need for integrated physical and mental health care for CKM patients.