Suboptimal glycemic control in type 2 diabetes: a key role for anhedonia?

Recent studies examining the relationship between depression and glycosylated hemoglobin (HbA(1c)) concentrations in patients with type 2 diabetes have yielded mixed findings. One explanation may lie in the heterogeneity of depression. Therefore, we examined whether distinct features of depression were differentially associated with suboptimal glycemic control. Cross-sectional baseline data from a dynamic cohort study of primary care patients with type 2 diabetes from the Eindhoven region, The Netherlands, were analyzed. A total of 5772 individuals completed baseline measurements of demographic, clinical, lifestyle and psychological factors between 2005 and 2009. The Edinburgh Depression Scale was used to assess symptoms of depressed mood, anhedonia and anxiety. Suboptimal glycemic control was defined as HbA(1c) values ≥7%, with 29.8% of the sample (n=1718) scoring above this cut-off. In univariate logistic regression analyses, anhedonia was significantly associated with suboptimal glycemic control (OR 1.29, 95% CI 1.09-1.52), while both depressed mood (OR 1.04, 0.88-1.22) and anxiety (OR 0.99, 0.83-1.19) were not. The association between anhedonia and glycemic control remained after adjustment for the other depression measures (OR 1.33, 1.11-1.59). Alcohol consumption and physical activity met criteria for mediation, but did not attenuate the association between anhedonia and glycemic control by more than 5%. Although diabetes duration was identified as a confounder and controlled for, the association was still significant (OR 1.20, 1.01-1.43). Studying different symptoms of depression, in particular anhedonia, may add to a better understanding of the relationship between depression and glycemic control.