Co-designing, evaluating and implementing online supportive care for endometriosis in Australia: study protocol for the hybrid type 1 effectiveness, cost-effectiveness and implementation randomised controlled trial of the CodeEndo program.

INTRODUCTION: Endometriosis is a chronic condition affecting up to 11% of people presumed female at birth by the age of 44 years, characterised by the growth of tissue similar to the lining of the uterus on other organs. Endometriosis significantly impacts health-related quality of life (HRQoL) and imposes a substantial burden on both individuals and the healthcare system. International guidelines recommend the interdisciplinary management of endometriosis due to its significant biopsychosocial burden; however, research aimed at exploring psychological approaches for endometriosis is limited. This trial aims to evaluate the effectiveness of CodeEndo, an online co-designed interdisciplinary supportive care program, compared with a waitlist control (WLC), on HRQoL and biopsychosocial outcomes in people with a diagnosis of endometriosis.

METHODS AND ANALYSIS: A hybrid type 1 effectiveness and implementation randomised controlled trial (RCT) will be conducted. Eligible participants will be randomly allocated to either the CodeEndo program (n=176) or WLC group (n=176) for 8 weeks. The primary outcome will be HRQoL, and secondary outcomes will include psychological symptoms (anxiety, depression, stress), self-efficacy, menstrual, bladder and gastrointestinal symptoms, pain, fatigue, sleep, exercise, diet, symptom bothersomeness and physical and psychological well-being, measured at 8 weeks post-randomisation (T2) and 6-month follow-up (T3). Cost-effectiveness will also be examined. Longitudinal qualitative individual interviews (up to n=40) will be conducted with participants who complete the CodeEndo program to explore benefits, barriers and facilitators of ongoing use. Additionally, the CodeEndo program will undergo evaluation by a group of endometriosis healthcare providers, who will assess potential barriers and facilitators to its real-world implementation. Various process evaluation strategies will also be measured to inform future implementation. Data analyses will incorporate mixed-effects regression models on an intention-to-treat basis, cost-consequences and cost-utility, dietary and qualitative thematic analysis.

ETHICS AND DISSEMINATION: This protocol received ethics approval from Deakin University Research Ethics Committee (DUREC Ref: 2024-157). Dissemination is expected to include peer-reviewed journal articles, reports, conference presentations as well as websites or social media platforms of relevant chronic pain organisations. Participants will be sent a summary of trial results.

TRIAL REGISTRATION NUMBER: ACTRN12623000598684p.