Abstract
Background
Diabetes, depression and aging have been associated with pro-inflammatory and prothrombotic state.

Aim
The aim of the study was to determine the plasma levels of thrombomodulin, plasminogen activator inhibitor-1 (PAI-1) and fibrinogen in elderly diabetic patients with and without depressive symptoms and to examine factors (including thrombomodulin, PAI-1, fibrinogen levels) associated with depressive symptoms in elderly patients with type 2 diabetes (T2DM).

Methods
A total of 276 T2DM elders were evaluated: 82 subjects with depressive symptoms and 194 controls. Data were collected concerning biochemical parameters and biomarkers.

Results
Plasma thrombomodulin, PAI-1 and fibrinogen were elevated in patients with depressive symptoms compared to controls. Thrombomodulin level was correlated with fibrinogen and PAI-1 levels. All parameters were correlated with the Geriatric Depression Scale-30 score. The univariate logistic regression models revealed that variables which increased the likelihood of diagnosis of depressive symptoms in elderly patients with T2DM were: female sex, smoking habit, longer duration of T2DM, hyperlipidemia, neuropathy, increased number of co-morbidities, higher BMI, and higher levels of total and LDL cholesterol, thrombomodulin, PAI-1 and fibrinogen. In addition, the multivariable analysis indicated that female sex, smoking habit, increased number of co-morbidities, higher BMI, and higher levels of LDL cholesterol and thrombomodulin are the predisposing factors for depressive symptoms.

Conclusions
Elderly diabetic patients with depressive symptoms have higher levels of thrombomodulin, PAI-1 and fibrinogen. Further prospective larger studies are needed to provide potential directions for the research, treatment and prevention of co-morbid depression and diabetes.

Keywords
Depressive symptomsDiabetesFibrinogenPAI-1Thrombomodulin