Gender-sensitive Enhancement of Common Weight Loss Strategies for Overweight and Obesity

Study Overview
=================
Brief Summary
-----------------
The major aim of the proposed study is to develop a gender-sensitive individually tailored add-on intervention that focusses on improving individual gender-specific SIRs (subjective illness representations) in obese or overweight individuals. We will investigate whether this will improve compliance with and long-term success of common weight loss interventions. The effectiveness of this intervention in every-day-life with regard to weight-related behavioral changes and weight loss will be evaluated within a randomized controlled setting.To enhance the applicability of the intervention in every-day-life and its dissemination we plan to develop a smart-phone-based intervention.

Official Title
-----------------
Gender-sensitive Enhancement of Common Weight Loss Strategies for Overweight and Obesity: a Personalized Smartphone App

Conditions
-----------------
Overweight and Obesity, Weight Loss, Gender

Intervention / Treatment
-----------------
* Behavioral: Smartphone-based interventional trial


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Obesity class I or II with subjectively experienced weight-related impairment and a current will to lose weight. Overweight (i.e. BMI between 25 and 29.9 kg/m²) with weight-related health problems and/or visceral adipose tissue and/or high psychosocial weight-related distress with a current will to lose weight. Exclusion Criteria: Obesity Class III (i.e. BMI >39.9 kg/m²). Current (or within the last 12 months) involvement in a structured weight loss intervention. Insulin-dependent type 1 diabetes. Previous or intended bariatric surgery. Current psychotherapeutic treatment of weight-related health problems. Weight-enhancing drugs. Drugs which promote weight-loss (e.g. anti-obesity drugs). Weight-enhancing health problems which are not yet treated. Cancerous disease within the last five years. Current substance-use disorders, depression, psychosis, suicidal tendency or pregnancy. Severe cognitive impairments. Insufficient knowledge of the german language. Binge-Eating Disorder or Bulimia nervosa.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention Group<br>The study will be a Smartphone-based interventional trial. To assess the effectiveness of the intervention weight- and eating-related behavior and cognitive and emotional responding as well as body-weight will be assessed using questionnaires and ecological momentary assessment (EMA) for one week at a pre- (T0), post- (T1) and two follow-up-assessments after six (T2) and 12 months (T3). | Behavioral: Smartphone-based interventional trial<br>* According to the SIRs the 12-week intervention will contain exercises from three out of six different key modules (e.g. self-efficacy, impulsivity). The remaining modules will be implemented as mini-modules during the end of the intervention phase. The study will be designed gender-sensitive instead of gender-dichotomous. This means that treatment contents will be individualized based on gender-related SIRs and not biological sex. Participants choose between two different styles of presentation for each module and the contents can be deepened within specific exercises.<br>|
| No Intervention: Control Group<br>Members of the control group will participate at each assessment. During the intervention phase they will receive treatment as usual. | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Physical Activity | The effectiveness of the intervention with regard to physical activity (motion sensors) will be investigated respecting gender-related differences. | The outcome will be measured at four assessments. At the beginning of the study (day 0), after finishing the app intervention (12 weeks later) and at to follow-up assessments 6 and 12 months later. | 
| Changes in Eating Behavior | The effectiveness of the intervention with regard to eating behavior (DEBQ) will be investigated respecting gender-related differences. | The outcome will be measured at four assessments. At the beginning of the study (day 0), after finishing the app intervention (12 weeks later) and at to follow-up assessments 6 and 12 months later. | 
| Changes in Subjective Illness Representations | The effectiveness of the intervention with regard to subjective illness representations (IPQ-R) will be investigated respecting gender-related differences. | The outcome will be measured at four assessments. At the beginning of the study (day 0), after finishing the app intervention (12 weeks later) and at to follow-up assessments 6 and 12 months later. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Weight Change | The effectiveness of the intervention with regard to weight will be investigated as assessed by BMI. | The outcome will be measured at four assessments. At the beginning of the study (day 0), after finishing the app intervention (12 weeks later) and at to follow-up assessments 6 and 12 months later. | 
| Changes in Emotional Competence | The effectiveness of the intervention with regard to subjective feeling of emotional competence (SEK-27) will be investigated respecting gender-related differences. | The outcome will be measured at four assessments. At the beginning of the study (day 0), after finishing the app intervention (12 weeks later) and at to follow-up assessments 6 and 12 months later. | 
| Changes in Impulsivity | The effectiveness of the intervention with regard to impulsivity (BIS-15) will be investigated respecting gender-related differences. | The outcome will be measured at four assessments. At the beginning of the study (day 0), after finishing the app intervention (12 weeks later) and at to follow-up assessments 6 and 12 months later. | 
| Changes in Coping Strategies | The effectiveness of the intervention with regard to coping strategies (Brief COPE) will be investigated respecting gender-related differences. | The outcome will be measured at four assessments. At the beginning of the study (day 0), after finishing the app intervention (12 weeks later) and at to follow-up assessments 6 and 12 months later. | 
| Changes in Weight-Related Life Quality: ORWELL-97 | The effectiveness of the intervention with regard to weight-related life quality (ORWELL-97) will be investigated respecting gender-related differences. | The outcome will be measured at four assessments. At the beginning of the study (day 0), after finishing the app intervention (12 weeks later) and at to follow-up assessments 6 and 12 months later. | 
| Changes in Self-Efficacy: General-Self-Efficacy-Scale | The effectiveness of the intervention with regard to self-efficacy (General-Self-Efficacy-Scale) will be investigated respecting gender-related differences. | The outcome will be measured at four assessments. At the beginning of the study (day 0), after finishing the app intervention (12 weeks later) and at to follow-up assessments 6 and 12 months later. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Gender, Overweight, Obesity, Intervention, Smartphone-App