Depression differed by midnight cortisol secretion, alexithymia and anxiety between diabetes types: a cross sectional comparison

BACKGROUND Increased prevalence of depression is found in both type 2 diabetes (T2D) and type 1 diabetes (T1D). Melancholia and atypical depression differ by cortisol secretion and clinical features. The aim was to compare the clinical presentation of T1D and T2D patients in relation to self-reported depression, self-reported anxiety, alexithymia, obesity, and midnight salivary cortisol (MSC). METHODS Comparative cross-sectional design. The participants were consecutively recruited from one hospital diabetes outpatient clinic: 24 T2D patients (31-59 years) and 148 T1D patients (32-59 years). Self-reported depression, anxiety and alexithymia were assessed by Hospital Anxiety and Depression scale and Toronto Alexithymia Scale-20. MSC, HbA1c, anthropometrics and data from medical records were collected. Multiple logistic regression analyses were performed. RESULTS Comparisons of prevalence between diabetes types showed for T2D/T1D: depression 25%/12% (P = 0.10); high MSC (≥9.3 nmol/L) 38%/22% (P = 0.13); alexithymia 25%/13% (P = 0.12); anxiety 38%/35% (P = 0.82). The prevalence of high MSC did not differ between depressed and non-depressed T2D patients (17% vs. 44%, P = 0.35), but differed between depressed and non-depressed T1D patients (53% vs. 18%, P = 0.003). The alexithymia prevalence differed between depressed and non-depressed T2D patients (67% vs.11%, P = 0.018), and between depressed and non-depressed T1D patients (47% vs. 11%, P < 0.001). The anxiety prevalence did not differ between depressed and non-depressed T2D patients (67% vs. 28%, P = 0.15), but differed between depressed and non-depressed T1D patients (76% vs. 30%, P < 0.001). The obesity prevalence (BMI ≥30 kg/m2) was 83% for depressed T2D patients and 6% for depressed T1D patients. In the T2D patients, depression was associated with alexithymia (Adjusted odds ratio (AOR) 15.0). In the T1D patients, depression was associated with anxiety (AOR 11.0), foot complications (AOR 8.5), HbA1C >70 mmol/mol (AOR 6.4), and high MSC (≥9.3 nmol/L) (AOR 4.8). CONCLUSIONS The depressed T2D patients had traits of atypical depression, without associated high MSC (≥9.3 nmol/L) and anxiety, but the association with alexithymia was strong. The depressed T1D patients had traits of melancholia with associated high MSC and anxiety. The obesity prevalence was high in depressed T2D patients and low in depressed T1D patients.