Towards a Better Understanding of Diabetes Distress, Depression and Poor Glycaemic Control in T2DM

Norbert Hermanns205 enrolled

Overview

DIA-LINK2 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 2 diabetes (T2DM). A total of 200 people with T2DM 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 T2DM.

DIA-LINK2 is a prospective observational study analysing longitudinal associations between diabetes distress (DD), depressive symptoms (DS) and glycaemic outcomes in people with type 2 diabetes (T2DM). 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 T2DM 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 T2DM. The findings shall be used to develop personalised interventions for people with diabetes and comorbid mental conditions (DD and DS).

Outcomes

Primary Outcomes

Depressive symptoms

Depressive symptoms are assessed using the 20-item Center for Epidemiologic Studies Depression Scale (CES-D), covering 20 symptoms of depression. Frequencies of the symptoms during the past week are scored on a 4-point Likert scale (from 0 - "rarely or non of the time" to 3 - "most or all of the time"). Item scores are summed to a total score ranging from 0 to 60, whereby higher values reflect higher depressive symptoms. A cut-off point at ≥ 22 points (found to have the best likelihood ratio for detecting depression within the German population) is used to establish elevated depressive symptoms in this study.

Time frame: 3-month follow-up

Diabetes Distress

Diabetes Distress is assessed as using the 20-item Problem Areas In Diabetes Scale (PAID). 20 potential problems related to living with diabetes are rated on a 5-point Likert scale (from 0 - "not a problem" to 4 - "serious problem"). Item scores are summed/transformed to a total score ranging from 0 to 100, whereby higher values reflect higher diabetes distress. A cut-off point at ≥ 40 points is commonly used to establish high diabetes distress, so too in this study.

Time frame: 3-month follow-up

HbA1c

HbA1c (estimated in %-points; mmol/mol values are calculated thereof) is used as a measure of glycaemic levels during past 3 months. It is estimated from a venous blood sample using high performance liquid chromatography (Tosho G11 analyser; meeting International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) standard) in this study. Higher values indicate less optimal glycaemic control, and values above 7.5% (58 mmol/mol) are considered to indicate glycaemic levels in need of improvement.

Time frame: 3-month follow-up

Secondary Outcomes

"Time in range" of glucose levels

Percentage of glucose values measured using CGM ("FreeStyle Libre 2" glucose monitoring system) during 4-week ambulatory assessment which are between 70 and 180 mg/dl (out of all measured values). Note that although the expression "time in range (TIR)" suggests a time measure, this is in fact estimated as a percentage score.