Evaluation of a Diabetes-specific Cognitive Behavioural Treatment for Subthreshold Depression

• Depressive Symptoms (CES-D-Score) [ Time Frame: Baseline, 12 months-FU ] [ Designated as safety issue: No ]
  The Center for Epidemiologic Studies Depression Scale (CES-D) is used for the assessment of depressive symptoms. The decicive measurement of this primary outcome variable is conducted 12 month after termination of the treatment (12 month follow up). The difference of the CES-D scores between baseline and 12 months follow up is calculated.
  
  

• Quality of life (EQ-5D Score, WHO-5 Score) [ Time Frame: Baseline,12 months-FU ] [ Designated as safety issue: No ]
  The EQ-5D and the WHO-5 Wellbeing Index are used for the assessment of quality of life. The decicive measurement of the outcome variable is conducted 12 month after termination of the treatment (12 month follow up). The differences of the test scores between baseline and 12 months follow up are calculated.
  
  
• Diabetes Distress (DDS-Score, PAID-Score) [ Time Frame: Baseline, 12 months-FU ] [ Designated as safety issue: No ]
  The Diabetes Distress Scale (DSS) and Problem areas in Diabetes Scale (PAID) are used for the assessment of diabetes-specific emotional distress. The decicive measurement of the outcome variable is conducted 12 month after termination of the treatment (12 month follow up). The differences of the test scores between baseline and 12 months follow up are calculated.
  
  
• Diabetes Self-care Activity (SDSCA Score) [ Time Frame: Baseline, 12 months-FU ] [ Designated as safety issue: No ]
  The Summary of Diabetes Self-care Activities Measure (SDSCA) is used for the assessment of diabetes self-care activitiy. The decicive measurement of the outcome variable is conducted 12 month after termination of the treatment (12 month follow up). The difference of the test scores between baseline and 12 months follow up is calculated.
  
  
• Diabetes Acceptance (AADQ Score) [ Time Frame: Baseline, 12 months-FU ] [ Designated as safety issue: No ]
  The Acceptance and Action Diabetes Questionnaire (AADQ) is used for the assessment of diabetes acceptance. The decicive measurement of the outcome variable is conducted 12 month after termination of the treatment (12 month follow up). The difference of the test scores between baseline and 12 months follow up is calculated.
  
  
• Inflammatory Markers (CRP, IL-6, IL-1RA, IL-18, TNF-alpha, DHEA-S, 5-HIAA, Cortisol) [ Time Frame: Baseline, 12 months-FU ] [ Designated as safety issue: Yes ]
  Inflammatory Markers are used for the assessment of distress-associated immune activity. The decicive measurement of the outcome variable is conducted 12 month after termination of the treatment (12 month follow up). The differences of the serum-/ uric concentrations between baseline and 12 months follow up is calculated.
  
  
• Health Care Costs [ Time Frame: Baseline, 12 months-FU ] [ Designated as safety issue: No ]
  The health-care costs are assessed by retrospective interviews refering to the last 6 months before each interview. Medical, medicinal and therapeutic interventions as well as other health-care supplies are assessed. The decicive measurement of the outcome variable is conducted 12 month after termination of the treatment (12 month follow up). The difference of the health-care costs before baseline and before 12 months follow up is calculated.
  
  
• Glycemic Control (HbA1c) [ Time Frame: Baseline, 12 months-FU ] [ Designated as safety issue: Yes ]
  The HbA1c represents the glycemic control during the last 3 months. The decicive measurement of the outcome variable is conducted 12 month after termination of the treatment (12 month follow up). The difference of the HbA1c values between baseline and 12 months follow up is calculated.
  
  
• Body Weight (kg) [ Time Frame: Baseline, 12 months-FU ] [ Designated as safety issue: No ]
  The body weight serves as a measure of life style change. The decicive measurement of the outcome variable is conducted 12 month after termination of the treatment (12 month follow up). The difference in the weight between baseline and 12 months follow up is calculated.
  
  

Elevated rates for depression in diabetic patients are of clinical significance for diabetology. Depressive disorders are doubled compared to patients without diabetes. A meta-analysis showed that a proportion of 20% of diabetic patients showed subthreshold depression, defined as elevated depressive symptoms without meeting criteria for clinical depression. Depression in diabetes is associated with a reduced quality of life, more diabetes related distress, and higher health related costs. But besides this, depression in diabetes seems to be an independent negative prognostic factor for morbidity and mortality. Furthermore subthreshold depression is a major barrier of an effective self-management of the disease.

Until now antidepressive therapies are only evaluated in clinically depressed diabetic patients. For the majority of depressed diabetic patients suffering from subthreshold depression no evaluated specific intervention concept exists. Since subthreshold depression often is associated with diabetes related distress a diabetes specific intervention was developed to support patients to increase their problem solving skills, modify their depressive cognitions and improve their coping with diabetes related distress. It consists of five sessions and is delivered as a group intervention.

This study is an efficacy trial. In this randomized trial the efficacy of this newly developed intervention is compared to a control condition consisting of five standard diabetes education lessons. The primary outcome variable is the reduction of depressive symptoms twelve months after the intervention. Secondary outcome variables are the quality of life, metabolic parameters, self-care behavior and other psychosocial aspects. Furthermore the possible covariation between change of depressive symptoms and inflammatory and immune markers will be analyzed.