Validity of the Center for Epidemiological Studies Depression scale in Type 2 diabetes

Objective: Depressive symptoms are common among people with Type 2 diabetes mellitus (T2DM). This study aimed to validate the 3-factor structure of the 14-item Center for Epidemiological Studies Depression (CES-D) scale proposed by Carleton et al. (2013) in a T2DM population. Methods: The CES-D was administered to consecutive patients with T2DM entering a rehabilitation program. Construct validity was assessed using confirmatory factor analysis. Subscale viability, differential item functioning, and associations with clinical characteristics were tested in bifactor models. Results: Among adults with T2DM (n = 305, age 56.9 +/- 11.1, 44.9% male, duration of diabetes 7.8 +/- 7.9 years, HbA1c 0.076 +/- 0.014%), the construct validity of Carleton's 3-factor solution (negative affective, positive affective and somatic symptoms) was confirmed, although negative affective and somatic symptoms were highly correlated (r = 0.926). The CES-D items can be summed to arrive at a total score (omega(H) = 0.869), but not subscale scores (omega(s) > 0.7). Differential item functioning was not found based on age or body mass index (BMI), but Item 1 ("I was bothered by things that don't usually bother me") was inflated in women and Item 7 ("I felt that everything I did was an effort") was inflated in those with higher glycosylated haemoglobin (HbA1c). The general depression factor decreased with age (beta = 0.247, p < 0.001) and increased with BMI (beta= 0.102, p = 0.041) but not HbA1 c (beta= 0.065, p = 0.461). Negative affective symptoms (beta = 0.743, p = 0.001), but not other depressive symptoms, were higher in women. Conclusions: The 14-item CES-D retained construct validity in adults with T2DM. Depressive symptoms were associated with younger age, female gender and BMI, but not with glycemic control. (C) 2016 Elsevier Inc. All rights reserved.