Purpose: Depression affects up to 20-25% of adults with diabetes and has been shown to predict all-cause mortality in older patients with diabetes. However, few well-designed studies have examined effects of depression on composite CVD outcomes, macrovascular complications, or microvascular complications in those with type 2 diabetes.
Methods: The 2,053 participants in the ACCORD Health-Related Quality of Life (HRQL) investigation completed the 9-item depression measure from the Patient Health Questionnaire (PHQ-9) at baseline and at 12, 36 and 48 months. A score of >10 on the PHQ-9 has been shown to have 77% sensitivity and 94% specificity to the diagnosis of major depression by structured psychiatric interview. Cox proportional-hazards regression models were used to estimate hazard ratios and 95% confidence intervals for the time varying impact of depression status on protocol-defined clinical endpoints with and without adjustment for age, gender, race/ethnicity, CHD and CHF status, HbA1c, lipids, blood pressure, BMI, smoker, alcohol consumption, living alone, glucose, blood pressure and lipid medications, baseline microvascular complications, education, duration of diabetes, ACCORD clinical center, and all ACCORD study intervention arm assignments.
Results: In fully adjusted models, total mortality was significantly increased both in those with PHQ score of >10 (HR=1.84; 95% CI 1.17 to 2.89) and major depression (HR= 2.24; 95% CI 1.24 to 4.06). Major depression had a borderline impact on the ACCORD combined macrovascular endpoint (cardiovascular death, nonfatal heart attack or stroke, or congestive heart failure) (1.42; 95% CI 0.99 to 2.04). Major depression was not significantly related to the ACCORD primary composite outcome (cardiovascular death or nonfatal heart attack or stroke) (HR=1.53; 95% CI 0.85 to 2.73) or to the ACCORD microvascular composite outcome (HR=0.93; 95% CI 0.53 to 1.62).
Conclusion: Depression is a significant independent predictor of increased mortality and may increase risk of subsequent macrovascular events in adults with type 2 diabetes CV events. The impact of depression status on subsequent microvascular complications is less certain.