Title: Feasibility study of how best to engage obese men in narrative SMS (short message system) and incentive interventions for weight loss, to inform a future effectiveness and cost-effectiveness trial
Funder: Chief Scientist Office, Scotland

Abstract: IMPORTANCE: In 2013, 26% of UK men were obese and this prevalence is increasing. Systematic reviews suggest that far fewer men than women engage in formal weight loss programmes, but if they do they are less likely to drop out MAIN RESEARCH QUESTIONS: Is a narrative SMS intervention with embedded behaviour change techniques (BCTs) and endowment incentives acceptable and feasible to deliver in a RCT? How can intervention components and delivery processes be optimised to increase reach, engagement and follow up of obese men? Are progression criteria met for a full RCT for one or both interventions? What are the likely recruitment and attrition rates? What would be the sample size for a full trial? AIM: To co-produce with PPI, an acceptable and feasible RCT design with wide reach to test a narrative SMS intervention with embedded BCTs, with and without an endowment incentive, compared to waiting list. This will inform a future pragmatic, full-scale effectiveness and cost-effectiveness trial DESIGN: A two phase feasibility study. Phase 1 will i) build a narrative SMS intervention with embedded BCTs for men using qualitative co-design, and ii) develop an endowment incentive drawing on insights from behavioural economics, existing evidence and men’s preferences for delivery based on survey/DCE evidence. An iterative mixed methods approach will use systematic review evidence, theory and learning from recent UK behaviour change trials to refine the interventions through PPI and user testing. Phase 2 is a 12 month feasibility RCT with 3 arms: SMS only; SMS and incentive; usual practice with waiting list for SMS intervention. Iterative mixed method data collection and analysis will help to refine the intervention parameters, design and processes in preparation for a potential full pragmatic effectiveness and cost-effectiveness RCT SETTING: 2 communities in Scotland with disadvantaged areas; differing in employment, ethnic groups, urban and rural access POPULATION: Obese adult men with BMI 30 or over and/or waist measurement 40 inches (102cm) or over. Recruitment through community venues (50%) and GP obesity registers (50%) (small payment required). Phase 1: a survey/DCE (n=1067 obese men); qualitative interviews/focus groups with 20-30 men and a stakeholder workshop (n=20) to finalise the intervention. Phase 2: 105 men randomised to three groups (n=35 each) and 24-30 qualitative interviews INTERVENTIONS: 1.Narrative SMS with embedded BCTs; 2.The same SMS plus endowment incentives CONTROL: Waiting list for narrative SMS intervention ALL GROUPS A pedometer for PA monitoring PRIMARY OUTCOMES: Acceptability and feasibility of recruitment, retention, intervention components, time points for verifying weight with assessor blinding, identifying core outcomes that are acceptable and matter for obese men SECONDARY OUTCOMES: Differential recruitment, engagement with narrative SMS and incentive components and attrition by socio-economic status and setting. Quality of motivation (intrinsic and extrinsic), satisfaction with weight loss, qualitative experiences, risk of incentive gaming. Meeting progression criteria, calculating the sample size and securing intervention funds for a full trial LIKELY FULL RCT PRIMARY OUTCOME: Weight loss at 1 year. SECONDARY: % weight loss, waist circumference, QALYs, costs IMPACT: A novel theory based intervention ready for a full RCT, with broad reach and with central delivery at scale

Lay abstract: Being obese causes 5% of deaths worldwide and puts people at greater risk of diseases like diabetes or some cancers. In 2013, 26% of UK men were obese, but men rarely participate in weight loss programmes. This study looks at whether two interventions which show promise can help obese men lose weight and keep it off. INTERVENTION 1: Sending (and receiving) text messages to a mobile phone. These will be written as though they come from other men who are also losing weight and include how-to-do-it, diet and physical activity tips, friendly humour and support. INTERVENTION 2: The same texts plus giving men money (up to £400) in a personal account at the start. The money will vary over a year according to whether weight targets are met e.g. our PPI group suggested losing 10% of body weight at 12 months after the start of the study. This is called an endowment incentive and is based on research showing that modest payment helps men change their diet and physical activity habits, and change is more likely if they avoid losing, rather than getting, something. WE WANT TO FIND OUT if the texts work better with incentives than alone. Both interventions are delivered from a computer and have potential to reach large numbers, including men who don’t use health services. This work will be done together with obese men and a charity for men to help us find the best ways to deliver the interventions to as many men as possible, including men in difficult life situations. THE STUDY HAS TWO PARTS: PHASE 1. We will decide text content to build a library; how often texts are sent; and how money is delivered according to weight measurements over a year. We will collect information, including scientific reports, a questionnaire, interviews (individuals, pairs or groups) with 20-30 obese men and discussions with 20 experts and men’s representatives. We will identify the best places in two Scottish regions where researchers will invite obese men to take part in the study (e.g. shopping centres, pharmacies, community centres, or other venues). PHASE 2. We will study whether it is acceptable and possible to randomise obese men (like tossing a coin) to three groups: texts only; texts and endowment incentive; or to a ‘control group’ who wait a year and then get the texts for 3 months. We will recruit 105 obese men from two regions. Half of the men will get an invitation letter from their GP. The other half will be approached in the community, given information about the study and invited to take part. They can take part if their trouser waist is 40 inches or more or their Body Mass Index is 30 or higher. We want to find out how long it takes to find 105 obese men who want to take part, how many come back to suitable venues at 3, 6 and 12 months to get weighed and answer questions about their quality of life, lifestyle and motivation. We will try and include men from all walks of life, so we will ask questions at the start like their age, address, who they live with, or if they have any illnesses like diabetes. At the end we will text all men in the study and ask them about their opinion of the study. We will also interview 18-24 men in more detail. THE STUDY WILL TELL US if our approach is acceptable, possible to deliver and if it could help men reduce obesity. If yes, then we will do a larger study to provide the evidence, costs, and benefits to individuals and society that governments and local services need to make decisions for roll out

Research activity codes: 6.6 PSYCHOLOGICAL AND BEHAVIOURAL
Health categories: CANCER AND NEOPLASMS;CARDIOVASCULAR;METABOLIC AND ENDOCRINE;ORAL AND GASTROINTESTINAL;STROKE