The association of comorbid depression with mortality in patients with type 2 diabetes

OBJECTIVE — We assessed whether patients with comorbid minor and major depression and type 2 diabetes had a higher mortality rate over a 3-year period compared with patients with diabetes alone. RESEARCH DESIGN AND METHODS — In a large health maintenance organization (HMO), 4,154 patients with type 2 diabetes were surveyed and followed for up to 3 years. Patients initially filled out a written questionnaire, and HMO-automated diagnostic, laboratory, and pharmacy data and Washington State mortality data were collected to assess diabetes com-plications and deaths. Cox proportional hazards regression models were used to calculate ad-justed hazard ratios of death for each group compared with the reference group. RESULTS — There were 275 (8.3%) deaths in 3,303 patients without depression compared with 48 (13.6%) deaths in 354 patients with minor depression and 59 (11.9%) deaths among 497 patients with major depression. A proportional hazards model with adjustment for age, sex, race/ethnicity, and educational attainment found that compared with the nondepressed group, minor depression was associated with a 1.67-fold increase in mortality (P 0.003), and major depression was associated with a 2.30-fold increase (P 0.0001). In a second model tha