Development of a Cystic Fibrosis Weight Management Programme:  protocol for a co-design study

Since the recent introduction of highly effective modulator therapies (HEMT), adults with cystic fibrosis (CF) have experienced significant health improvements. However, HEMTs can also lead to weight gain, and over 30% of adults living with CF, are now overweight or obese. The English National Health Service digital Weight Management Programme (NHS digital WMP) is offered to adults with obesity to support weight loss. This programme may not meet the complex health needs of people living with CF and may not address the established diet and physical activity behaviours that may contribute to weight gain in this population. Methods This paper outlines the steps to co-develop a CF-specific weight management programme (CF WMP), designed to be delivered alongside an NHS digital WMP. The CF-specific programme will be developed in collaboration with people with CF who have overweight or obesity (PwCF ^ow/ob) and professional stakeholders, using the three phases of the Person Based Approach (PBA); planning, co-designing and optimising. Planning Mixed-methods research with PwCF ^ow/ob and CF health care professionals will identify the barriers and facilitators to healthy eating and physical activity experienced by PwCF ^ow/ob. This will inform the guiding principles to underpin the co-design of the CF WMP and how it will address the dietary and physical activity behavioural needs of PwCF ^ow/ob to ensure it is engaging, acceptable and motivating. Co-design: a series of participatory workshops with PwCF ^ow/ob and key stakeholders will use guiding principles to specify design objectives and corresponding intervention features. Optimising: think aloud interviews with PwCF ^ow/ob will gather feedback on the CF WMP, to iteratively refine the programme.

The resulting CF WMP will extend the usability of an NHS digital WMP to adults with CF, to better ensure it meets their needs, which have changed since the introduction of HEMT.