Comorbid depression and risk of cardiac events and cardiac mortality in people with diabetes: A systematic review and meta-analysis

To examine the association of comorbid occurrence of diabetes and depression with risk of cardiovascular endpoints including cardiovascular mortality, coronary heart disease and stroke. Research design and methods: A systematic review and metaanalysis. We searched PUBMED/MEDLINE, Medscape, Cochrane Library, CINAHL, EMBASE and Scopus databases assessing cardiac events and mortality associated with depression in diabetes up until 1 December 2018. Pooled hazard ratios were calculated using random- effects models. Results: Nine studies met the inclusion criteria. The combined pooled hazard ratios showed a significant association of cardiac events in people with depression and type 2 diabetes, compared to those with type 2 diabetes alone. For cardiovascular mortality the pooled hazard ratio was 1.48 (95% CI: 1.185, 1.845), p = 0.001, for coronary heart disease 1.37 (1.165, 1.605), p < 0.001 and for stroke 1.33 (1.291, 1.369), p < 0.001. Heterogeneity was high in the meta-analysis for stroke events (I-squared = 84.7%) but was lower for coronary heart disease and cardiovascular mortality (15% and 43.4% respectively). Meta-regression analyses showed that depression was not significantly associated with the study level covariates mean age, duration of diabetes, length of follow-up, BMI, sex and ethnicity (p < 0.05 for all models). Only three studies were found that examined the association of depression in type 1 diabetes, there was a high degree of heterogeneity and data synthesis was not conducted for these studies. Conclusions: We have demonstrated a 47.9% increase in cardiovascular mortality, 36.8% increase in coronary heart disease and 32.9% increase in stroke in people with diabetes and comorbid depression. The presence of depression in a person with diabetes should trigger the consideration of evidence-based therapies for cardiovascular disease prevention irrespective of the baseline risk of cardiovascular disease or duration of diabetes.