Increased Risk of Cardiovascular Disease and Mortality in Patients with Diabetes and Coexisting Depression: A Nationwide Population-Based Cohort Study

Background: Previous studies have suggested that depression in patients with diabetes is associated with worse health outcomes. The aim of this study was to evaluate the risk of cardiovascular disease (CVD) and mortality in patients with diabetes with comorbid depression. Methods: We examined the general health check-up data and claim database of the Korean National Health Insurance Service (NHIS) of 2,668,615 participants with type 2 diabetes mellitus who had examinations between 2009 and 2012. As NHIS database has been established since 2002, those who had been diagnosed with depression or CVD since 2002 were excluded. The 2,228,443 participants were classified into three groups according to the claim history of depression; normal group (n=2,166,979), transient depression group (one episode of depression, n=42,124) and persistent depression group (at least two episodes of depression, n=19,340). The development of CVD and mortality were analyzed from 2009 to 2017. Results: Those with depression showed a significantly increased risk for stroke (transient depression group: hazard ratio [HR], 1.20; 95% confidence interval [CI], 1.15 to 1.26) (persistent depression group: HR, 1.54; 95% CI, 1.46 to 1.63). Those with depression had an increased risk for myocardial infarction (transient depression group: HR, 1.25; 95% CI, 1.18 to 1.31) (persistent depression group: HR, 1.38; 95% CI, 1.29 to 1.49). The persistent depression group had an increased risk for all-cause mortality (HR, 1.66; 95% CI, 1.60 to 1.72). Conclusion: Coexisting depression in patients with diabetes has a deleterious effect on the development of CVD and mortality. We suggest that more attention should be given to patients with diabetes who present with depressive symptoms.