Depressive symptoms predict change in glycemic control in adolescents with type 1 diabetes: rates, magnitude, and moderators of change

Objective: To determine whether depressive symptoms in adolescents with type 1 diabetes predict change in glycemic control over time. Research design and methods: A total of 145 adolescents (aged 13-18 yr) participated in two study visits (baseline and 6 months). They completed a measure of depressive symptoms (Children's Depression Inventory; CDI) and had their A1c values and adherence to blood glucose monitoring (BGM) documented. Results: Three variables predicted A1c change over 6 months: CDI change score (B = 0.11; p < 0.001), BGM frequency at baseline (B = -0.21; p = 0.03), and A1c at baseline (B = -0.23; p = 0.002). A three-way interaction among these variables was significant (p < 0.01) and showed that adolescents with high adherence to BGM who were achieving optimal glycemic control (<= 7.5%) at baseline were resistant to increasing A1c values, even if depressive symptoms worsened. However, as adherence to BGM declines, there is a synergistic effect with depressive symptoms to accelerate the increase of A1c values over time, making it more difficult to bring A1c back to optimal levels. Conclusions: Results suggest that depressive symptoms are important predictors of A1c change by themselves as well as when considered with adherence to BGM. There is a need to screen for depressive symptoms and expand and develop prevention and intervention strategies in order to put adolescents with type 1 diabetes in the best position for optimal glycemic control.