The core outcome set for studies on feminizing genital gender-affirming surgery: findings from the GenderCOS project
Vallinga, Marleen S Roijer, Philippine J Pidgeon, Thomas E Angelini, Matteo Ceulemans, Aline Bakker, Alex Carrière, Brenda Rashid, Tina Bellringer, James Belinky, Javier
Vallinga, Marleen S
Roijer, Philippine J
Pidgeon, Thomas E
Angelini, Matteo
Ceulemans, Aline
Bakker, Alex
Carrière, Brenda
Rashid, Tina
Bellringer, James
Belinky, Javier
Affiliation
Nuffield Health Parkside Hospital; The dudley Group NHS Foundation Trust; Nottingham Centre for Transgender Health
Other Contributors
Publication date
2025-07-01
Collections
Research Projects
Organizational Units
Journal Issue
Abstract
BACKGROUND: Feminizing genital gender-affirming surgery (gGAS) comprises various surgical procedures and techniques. Comprehensive knowledge of the outcomes of all procedures and techniques is fundamental for informed decision-making. However, in current research on feminizing gGAS there is significant heterogeneity in reported outcomes. Standardization of outcome measurement is therefore urgently required. This study aimed to develop a Core Outcome Set (COS) for feminizing gGAS.
METHODS: A multidisciplinary, international study steering group comprising 16 panellists from Europe, the United Kingdom, North America, and South America-including health care professionals and transgender individuals-was appointed to guide the development of a COS. The steering group convened on 16 June 2022, 28 September 2023, 2 May 2024, and 29 August 2024. The study involved three phases: (i) relevant outcomes were identified through a literature review and focus groups with transgender and gender-diverse people; (ii) stakeholders were invited to participate in an international Delphi study to reach consensus on the key outcomes; (iii) a consensus meeting was held to reach a final consensus on the COS.
FINDINGS: Initial data collection yielded 2621 unique outcomes. This number was reduced to 39 potential outcomes for the Delphi process through a structured selection process. The Delphi rounds encompassed February, May and July 2024 respectively. Following the consensus meeting in September 2024, a final list of 11 outcomes was agreed, of which six are patient-reported outcomes. Seven outcomes apply to all feminizing gGAS procedures and four are specific to vaginoplasty procedures involving the creation of a vaginal canal.
INTERPRETATION: Adoption of the COS for feminizing gGAS could ensure that the most relevant outcomes in clinical research are measured and reported in a standardized way. Future studies adopting these suggested outcome measures could reduce the heterogeneity of reported outcomes across studies and working to improve the quality of research and care.
FUNDING: None received.
Citation
Vallinga MS, Roijer PJ, Pidgeon TE, Angelini M, Ceulemans A, Bakker A, Carrière B, Rashid T, Bellringer J, Belinky J, Buncamper M, Morrison SD, Bouman WP, van de Grift TC, Bouman MB, Mullender MG. The core outcome set for studies on feminizing genital gender-affirming surgery: findings from the GenderCOS project. EClinicalMedicine. 2025 Jul 1;85:103323. doi: 10.1016/j.eclinm.2025.103323
Type
Article