Feasibility trial of acceptance and commitment therapy in bariatric patients

INTERVENTION: Design This will be a feasibility study for a single‐centre, parallel group, single blind, two arm trial with participants randomised to either ACT or control. It will provide information about recruitment and characteristics of the proposed outcome measures to inform an application for a definitive RCT of ACT group therapy for post bariatric surgery patients. The definitive RCT will investigate the effectiveness of ACT in maintaining weight loss, improving wellbeing and healthy lifestyle behaviour and reducing health service costs when delivered at a time point at which there is a high risk of weight regain and reoperation. The feasibility study will compare ACT group therapy at 15‐18 months post‐surgery with usual care (support group) over 10 weeks. Setting Recruitment and research activity will take place within a London‐based NHS weight‐loss service that carries out bariatric surgery and its associated aftercare. No recruitment problems are expected; however, should the rate of recruitment or follow‐up be below that expected, the trialists will invite another local weight loss surgery service to participate. All elements of study participation will take place at the above‐mentioned site(s), or, if necessary, the participants’ homes via telephone interview (for follow up time points 3 and 6 months). Sample size As this is a feasibility study and no hypothesis testing will occur, a power calculation has not been conducted. Literature suggests that at least 30‐40 participants are needed for a pilot RCT, however, and we will therefore recruit 58 participants to allow for a 30% drop out rate. While the trialists are not aiming to test for a difference between groups, they will estimate the characteristics of the proposed outcome measures and will calculate the differences between the groups with 95% confidence intervals to inform the power calculation for the definitive trial. They have not estimated the precision of their descriptive outcomes as they will use the CONDITION: Specialty: Mental Health, Primary sub‐specialty: Study not assigned to a MH Clinical Studies Group; UKCRC code/ Disease: Mental health/ Unspecified mental disorder, Metabolic and Endocrine/ Obesity and other hyperalimentation ; Mental and Behavioural Disorders INCLUSION CRITERIA: Adults (aged 18 or over) who have undergone bariatric surgery >1 year ago and have given their consent for the study PRIMARY OUTCOME: The primary aim of this study is to establish the feasibility of a definitive RCT of the effectiveness of ACT for preventing weight regain in post‐bariatric surgery patients. Outcomes to be assessed are:; 1. The willingness of participants to be randomised. This will be assessed using the number of eligible participants minus the number of patients who agree to randomisation (measured at screening); 2. The number of eligible patients coming through clinic. This will be assessed by calculating the percentage of patients who meet eligibility criteria (measured at baseline); 3. Recruitment and completion rates, follow‐up rates, response rates to questionnaires, adherence/compliance rates to the intervention and trial procedures. This will be assessed by the number of participants who consent to participate and who remain in the study until 12 month follow‐up, the number of participants who provide complete datasets, and the number of participants who attend all 10 sessions of intervention/support group. Reasons for attrition will also be recorded; 4. Time needed to collect data. This will be assessed by how long it takes participants to complete the battery of questionnaires at each time point (measured at baseline, 3, 6 and 12 month follow‐up); 5. The acceptability of the intervention to participants. This will be assessed by a visual analogue scale (measured at 12 month follow‐up); 6. The standard deviation of potential outcome measures for a future trial (to estimate the required sample size for a future trial) (measured at study close‐out); 7. Information to inform the undertaking of an economic evaluation in the definitive RCT and to pilot the data collection methods. This will be assessed by calculating the cost of the intervention and examining data on patients’ resource use on the CSRI (measured at study close‐out) SECONDARY OUTCOME: The measures that will be evaluated within this feasibility study are as follows:; ; MEASURES TO TEST THE PROCESS OF THE ACT INTERVENTION:; 1. The ability to tolerate distress measured by the Distress Tolerance Scale at baseline, 3, 6, & 12 month follow‐up; 2. Present moment awareness and acceptance measured by the Philadelphia Mindfulness Scale at baseline, 3, 6 & 12 month follow‐up; 3. Experiential distancing measured by the Drexel Defusion Scale at baseline, 3, 6 & 12 month follow‐up; 4. The extent to which an individual is able to accept or tolerate physical or psychological discomfort, measured by the Physical Activity Acceptance Questionnaire at baseline, 3, 6 & 12 month follow‐up; 5. Acceptance of food related thoughts and urges measured by the Food Acceptance and Action Questionnaire at baseline, 3, 6 & 12 month follow‐up; ; OBESITY AND HEALTH OUTCOMES:; 1. Class of obesity measured by the Kings Obesity Criteria at baseline and 12 month follow‐up; 2. Levels of physical activity measured by the International Physical Activity Questionnaire at baseline, 3, 6 & 12 month follow‐up; 3. Food intake measured by the Automated Self‐Administered 24‐hr Dietary Recall at baseline, 3, 6 & 12 month follow‐up; 4. Adherence to a Mediterranean diet measured by the Brief Mediterranean Diet Questionnaire at baseline, 3, 6 & 12 month follow‐up; 5. Level of risk to alcohol harm measured by the Alcohol Use Disorders Identification Test at baseline, 3, 6 & 12 month follow‐up; 6. Eating behaviour, in terms of restrained, emotional, and external eating, measured by the Dutch Eating Behaviour Questionnaire at baseline, 3, 6 & 12 month follow‐up; ; WELLBEING OUTCOMES:; 1. Levels of anxiety and depression measured by the Hospital Anxiety and Depression Scale at baseline, 3, 6 & 12 month follow‐up; ; HEALTH ECONOMIC OUTCOMES:; 1. Service utilisation, income, accommodation and other cost‐related variables measured by the Client Service Receipt Inventory at baseline, 3, 6 & 12 month follow‐up; 2. Health‐related quality of life measured by the EQ‐5D at baseline, 3, 6 & 12 month follow‐up; 3. Capability wellbeing measured by the ICECAP‐A at baseline, 3, 6 & 12 month follow‐up