Comorbid Depression and Risk of Cardiac Events and Cardiac Mortality in People with Diabetes: A Systematic Review and Meta-Analysis

Abstract

Objective: To examine the comorbid occurrence of diabetes and depression with clinical CVD endpoints, by conducting a systematic review and meta-analysis of observational studies. Research Design and Methods: 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 all showed a significant risk 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 the impact of 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.

Funding Statement: The authors state: "None."

Declaration of Interests: The authors stated: "None relevant to declare."

Ethics Approval Statement: No separate ethical approval was required for the conduct of this study, as any necessary ethical approval was obtained for each of the individual studies contributing data to the meta-analysis.

The authors conducted this literature-based review using a protocol registered in the PROSPERO International prospective register of systematic reviews (ID=CRD42017083968) and in accordance with guidelines of PRISMA.