Depression and Diabetes Control Trial

This randomised controlled trial evaluates a cognitive-behavioural intervention for diabetes patients with suboptimal glycaemic control and comorbid depressive symptoms and/or diabetes distress. The main outcome is the improvement of suboptimal glycaemic control (HbA1c). Secondary outcomes are effects on depressive symptoms, diabetes distress, self-care behaviour, diabetes acceptance and quality of life. The treatment group will be treated with a cognitive-behavioural group treatment comprising specific interventions to improve glycaemic control and reduce diabetes distress as well as depressive symptoms. The control group will receive treatment-as-usual. A total of 212 study participants will be included. A secondary study objective is to analyse associations of suboptimal glycaemic control, depressive symptoms and diabetes distress with inflammatory markers.

Suboptimal glycaemic control is an established risk factor for the development of serious long-term complications of diabetes. Moreover, it is associated with elevated risks of significant hyperglycaemic acute events such as hyperosmolar hyperglycemic state or diabetic ketoacidosis. Hence, patients with diabetes and persistent suboptimal glycaemic control are at higher risk of having a rather poor prognosis.

Besides physiological and medical factors, psychological problems have been found to predict suboptimal glycaemic control. A number of studies found depressive symptoms to be independently associated with hyperglycaemia. Others focussed on diabetes-specific affective problems - the so called diabetes distress - and suggested this factor to be of great importance. Finally, some studies found that depressive symptoms and diabetes distress may interact, with the coocurrence of these factors being associated with the highest risk or suboptimal glycaemic control. The results correspond to other findings suggesting that both depressive symptoms and diabetes distress are often associated with reduced diabetes self-care, which can explain the associations of those factors with hyperglycaemia.

On the other hand, suboptimal glycaemic control could also be an explanation for affective problems - either mediated by physiological mechanisms or psychological ones, e.g. dissatisfaction or guilt. Hence, it is valid to assume that the link between depressive symptoms and/or diabetes distress may be bidirectional - although evidence to support this assumption is missing.

Following this evidence and background, the investigators designed the a to analyse the relationships between suboptimal glycaemic control, depressive symptoms and diabetes distress in diabetes using a prospective study design. The study is a randomized trial in which a cognitive-behavioural group treatment is compared to a treatment-as-usual condition (standard diabetes education) regarding their efficacy in improving suboptimal glycaemic control. 212 diabetes patients with suboptimal glycaemic control (HbA1c value \> 7.5%) and elevated depressive symptoms (Center for Epidemiologic Studies Depressions Scale score ≥ 16) and/or elevated diabetes distress (Problem Areas In Diabetes Scale score ≥ 40) will be randomly assigned to either the treatment group or treatment-as-usual. The primary outcome is the improvement of suboptimal glycaemic control (reduction of HbA1c) in the 12-month follow-up. As secondary outcomes positive baseline-to-follow up changes regarding depressive symptoms, diabetes distress, diabetes self-care behaviour, diabetes acceptance and quality of life are assessed.

A second study objective is to analyse cross-sectional and prospective associations of suboptimal glycaemic control, depressive symptoms and diabetes distress with serum levels of the following inflammatory markers: hsCRP, IL-6, IL-18, IL-1Ra, MCP-1 and Adiponectin. Potential effects of the treatment groups on these markers will also be examined.

Eligibility Criteria:
Inclusion Criteria:

* Age between 18 and 70
* Diabetes mellitus type 1 or type 2
* Diabetes duration ≥ 1 year
* Suboptimal glycaemic control (HbA1c \> 7,5%)
* Elevated depressive symptoms (CES-D score ≥ 16) and/or elevated diabetes distress (PAID score ≥ 40)
* Sufficient language skills
* Written informed consent

Exclusion Criteria:

* Severe major depressive disorder according to ICD-10
* Current psychiatric and/or psychotherapeutic treatment
* Current antidepressive medical treatment
* Suicidal ideation
* Acute mental disorder of the following type: schizophrenia or other psychotic disorder, bipolar disorder, severe eating disorder (anorexia nervosa, bulimia nervosa), substance use disorder
* History of personality disorder
* Severe somatic illnesses: dialysis-dependent nephropathy, acute cancer, severe heart disease (NYHA III - IV), severe neurologic illness (e. g. MS, dementia), severe autoimmune disease
* Terminal illness
* Bedriddenness
* Guardianship