Importance Depression has been identified as a risk factor for dementia among patients with type 2 diabetes mellitus but the cognitive domains and patient groups most affected have not been identified.
Objective To determine whether comorbid depression in patients with type 2 diabetes accelerates cognitive decline.
Design A 40-month cohort study of participants in the Action to Control Cardiovascular Risk in Diabetes-Memory in Diabetes (ACCORD-MIND) trial.
Setting Fifty-two clinics organized into 6 clinical networks across the United States and Canada.
Participants Two thousand nine hundred seventy-seven participants with type 2 diabetes at high risk for cardiovascular events.
Intervention The Digit Symbol Substitution Test, Rey Auditory Verbal Learning Test, and the modified Stroop test were used to assess cognition. The 9-item Patient Health Questionnaire was used to assess depression.
Main Outcomes and Measures Mixed-effects statistical models were used to analyze cognitive test outcomes incorporating depression as a time-dependent covariate.
Results Participants with scores indicative of depression (9-item Patient Health Questionnaire, 10) showed greater cognitive decline during 40-month follow-up on all tests...