PURPOSE We wanted to identify risk factors associated with the development of major depressive disorder (MDD) among patients with type 2 diabetes over time.
METHODSIn a noninterventional study, 338 adult patients with type 2 diabetes and no MDD diagnosis at baseline were assessed 3 times during 18 months (9-month intervals) to ascertain predictors of MDD. We tested a model incorporating personal, behavioral, biologic, and psychosocial variables to identify predictors of MDD. Exploratory analyses tested whether current negative affect mediated the relationship between predictors and subsequent MDD. We also conducted a stratifi ed analysis of moderate vs high negative affect to explore whether level of baseline negative affect mediated the relationship between specifi c predictors and MDD.RESULTS Prior MDD and negative affect predicted future development of MDD. In subpopulations stratifi ed by moderate negative affect, negative life events, an elevated body mass index (BMI), prior MDD, and poor control of glycated hemoglobin (hemoglobin A 1c ) each predicted MDD. In subpopulations stratifi ed by elevated negative affect, negative life events and poor control of hemoglobin A 1c predicted MDD. Current negative affect partially mediated the relationship between prior MDD and subsequent MDD, as well as the relationship between negative life events and subsequent MDD.
CONCLUSIONSAlthough negative affect at baseline was the primary predictor of subsequent MDD, when stratifi ed by negative affect, negative life events, BMI, and poor control of hemoglobin A 1c also predicted MDD. Thus, life stresses and patients' disease-related concerns are important when understanding what predicts subsequent MDD. Addressing depressive symptoms and broader life context issues expands the scope of a potential intervention to reduce the risk of developing MDD in persons with type 2 diabetes. 2011;9:115-120. doi:10.1370/afm.1212.
Ann Fam Med
INTRODUCTIOND epression is a common comorbidity among patients with type 2 diabetes. It is associated with increased health care costs, disability, functional impairment, and mortality.1,2 Patients with type 2 diabetes are 52% more likely to develop major depressive disorder (MDD) than the general population, 3 and most of these patients are managed in primary care.
4Although several studies have suggested all patients with diabetes be screened for MDD, 5,6 the ability to identify subsets of patients with type 2 diabetes who are at risk would channel scarce resources and focus attention on a vulnerable population. 7,8 We undertook this study in an effort to identify biologic, behavioral, and psychosocial characteristics at baseline that predict the onset of MDD among primary care patients with diabetes.
METHODSOur study was of a 3-wave, 18-month, noninterventional, longitudinal design that included a primary care sample of 506 patients with type 2