PARIS: Protocol for a single centre feasibility study to increase Physical Activity and reduce sedentaRy behavIour after bariatric Surgery

Introduction: Bariatric surgery offers the most effective treatment for severe obesity (BMI ≥35 with obesity related complications or ≥40 without);it induces significant weight loss and can improve associated complications such as type 2 diabetes (Gloy et al., 2013). However, it is not a panacea;weight can be regained and complications can return (Magro et al., 2008;Cooper et al., 2015;DiGiorgi et al., 2010). As a result, there is an increasing focus on how patients should be supported to optimise their longer term outcomes (NICE, 2014). Evidence shows that increasing physical activity after surgery can help patients to optimise their weight, fat mass loss and physical fitness compared to those who do not (Bellicha et al., 2018;Ren et al., 2018) and that short periods of sedentary behaviour can have negative consequences (Bowden Davies et al., 2019). However, there is an evidence gap as research tends to focus on the physiological effects of physical activity and sedentary behaviour rather than how to support patients to change these behaviours. Methods: PARIS is a single arm feasibility study of a theory and evidence- based group intervention that targets physical activity and sedentary behaviour in patients who have had bariatric surgery. Intervention objectives are the result of the evidence from the literature and primary qualitative research conducted with patients, clinicians and commissioners (who have responsibility for procuring post-surgical and follow up care). Intervention objectives will be met over the course of six sessions held over six weeks using behaviour change techniques from the behaviour change technique taxonomy V1 (Michie et al., 2013). The intervention will be delivered online using Zoom, in a group of up-to six participants who have had surgery within the previous five years. Groups will last upto and hour and a half and will be facilitated by an experienced physiotherapist and supported by an intervention handbook. Qualitative semi-structured interviews after the intervention will be used to explore participants views including the acceptability of the intervention. Results: Feasibility outcomes include the rate of retention, intervention fidelity and engagement. The study will also seek to generate the data for a sample size calculation where physical activity or sedentary behaviour is the primary outcome. Study outcomes include self-reported and objectively measured physical activity and sedentary behaviour using the International Physical Activity Questionnaire-Long Form and ActiGraph Link wrist worn accelerometer. Quantitative data will be analysed descriptively and qualitative data analysed according to the constant comparative approach of Grounded Theory. Conclusion: This is a pragmatic single arm feasibility study evaluating a theory and evidence-based group intervention, and is the result of evidence synthesis, review of relevant theory and primary qualitative research with three key stakeholder groups. It is the first study of a group behaviour change intervention delivered online to a clinically vulnerable population during the Covid-19 pandemic.