Towards a Better Understanding of Diabetes Distress, Depression and Poor Glycaemic Control (DIA-LINK Study)

The DIA-LINK Study is a prospective observational study analysing longitudinal associations and mediating links between diabetes distress (DD), depressive symptoms (DS) and glycaemic outcomes in people with type 1 diabetes (T1DM). A total of 200 people with T1DM with different levels of DD and DS are to be enrolled.

At baseline, all participants are assessed for DD and DS, psychological and stress-related variables, self-reported self-management, HbA1c and inflammatory markers.

This is followed by a 4-week ambulatory assessment period including continuous glucose monitoring (CGM), continuous activity tracking and daily event sampling regarding sleep, stress levels, mood and diabetes-related issues; additionally, cortisol levels are assessed on four days within this period.

Three months after baseline, a follow-up assessment covers DD and DS levels, stress-related variables, self-reported self-management, HbA1c and final CGM assessment.

The analyses aim to establish risk factors/protective factors regarding DD and DS, their relative impact on glycaemic outcomes and potential mediation of the associations by behavioural (e.g. self-management, physical activity), physical (e.g. heart rate variability, inflammatory activity) and mental variables (subjective stress level) in T1DM.

The DIA-LINK Study is a prospective observational study analysing longitudinal associations between diabetes distress (DD), depressive symptoms (DS) and glycaemic outcomes in people with type 1 diabetes (T1DM). A variety of behavioural, physical and mental variables are assessed to analyse the mediating links between DD, DS and glycaemia.

A total of 200 people with T1DM are enrolled according to DD (PAID ≥ / \< 40) and DS (CES-D ≥ / \< 22) scores so that four groups (n = 50 persons each) with varying levels of DD and DS are established: 1. PAID \< 40 and CES-D \< 22 (no DD, no DS); 2. PAID ≥ 40 and CES-D \< 22 (DD, no DS); 3. PAID \< 40 and CES-D ≥ 22 (DS, no DD); 4. PAID ≥ 40 and CES-D ≥ 22 (DD and DS).

At baseline, all participants are assessed for relevant psychological and stress-related variables (daily hassles, life events, diabetes-related problems and fears, coping styles, resilience, diabetes acceptance, depression) as well as self-reported diabetes self-management using validated self-report scales and interviews; HbA1c and selected markers of inflammation (hsCRP, IL-6, IL-18, IL1Ra) are analysed from venous blood samples.

This is followed by a 4-week ambulatory assessment period including continuous glucose monitoring (CGM) (to establish time in range, glucose variability and times in hypo/hyperglycaemia), continuous activity tracking regarding general activity, movement, sleep and heart rate using a wristband as well as event sampling regarding sleep quality, stress levels, mood and diabetes-related issues four times daily using a smartphone app. Additionally, salivary cortisol levels are estimated on four consecutive days (each including a morning, afternoon and night time sample) within this period.

Three months after baseline, a follow-up assessment is performed which includes self-report measures of DD and DS, stress-related variables and diabetes self-management, HbA1c estimation from venous blood samples and final CGM assessment over 14 days.

The collected data are used to analyse risk factors/protective factors regarding DD and DS, their relative impact on glycaemic outcomes and potential mediation of the associations by behavioural (e.g. self-management, physical activity), physical (e.g. heart rate variability, inflammatory activity) and mental variables (subjective stress level) in T1DM.

The findings shall be used to develop personalised interventions for people with diabetes and comorbid mental conditions (DD and DS).

Eligibility Criteria:
Inclusion Criteria:

* Type 1 Diabetes
* Diabetes duration at least 1 year
* Age between 18 and 70 years
* Sufficient German language skills
* Informed consent
* Smartphone available

Exclusion Criteria:

* Capacity for consent lacking
* Illness with significant impairment of cognitive functioning (e.g. dementia)
* Severe somatic illness or mental disorder which interferes with study participation or might confound the results (dialysis-dependent renal failure; heart failure, i.e. New York Heart Association (NYHA) class III or IV; cancer requiring treatment; schizophrenia/psychotic disorder; bipolar disorder; severe eating disorder F50.0/F50.2; personality disorder)
* Terminal illness
* Being bedridden