Little is known about the frequency of depression in adults with type 1 diabetes (T1D) or its relationship to diabetes outcomes. The T1D Exchange clinic registry allowed us to explore depression in a large, heterogeneous sample.RESEARCH DESIGN AND METHODS
Participants ≥18 years old (N = 6,172; median age 34 years; median diabetes duration 16 years; 55% female; and 89% non-Hispanic white) completed the eight-item Patient Health Questionnaire (PHQ-8), a validated, reliable measure of current depression. Probable major depression was defined in four ways: PHQ-8 ≥10, PHQ-8 ≥12, per diagnostic algorithm, and as a continuous variable. Characteristics and clinical outcomes of those with and without depression were compared using logistic and linear regression models.RESULTS
A total of 4.6–10.3% of participants were classified as probable major depression depending on how defined. Participants classified as depressed were more likely female, nonwhite race/ethnicity, to have a lower household income and lower education level, to exercise less often, to miss insulin doses, and to have one or more complications (neuropathy, nephropathy, treatment for retinopathy, or cardiovascular/cerebrovascular disease) (all P < 0.01). HbA1c was higher in the depressed versus not depressed groups (8.4 ± 1.7% [68 ± 8.6 mmol/mol] vs. 7.8 ± 1.4% [62 ± 15.3 mmol/mol]; P < 0.001). Occurrence of one or more diabetic ketoacidosis events (11 vs. 4%; P < 0.001) and one or more severe hypoglycemic events (18 vs. 9%; P < 0.001) in the past 3 months was higher among depressed participants.CONCLUSIONS
In the T1D Exchange clinic registry, adults with probable major depression have worse clinical outcomes than those not depressed. Whether identification and treatment of depression improves diabetes outcomes requires study. Depression is common in T1D, and better identification and treatment of this comorbid condition is needed.