Navigating toward standardization: A systematic review mapping outcome measures in masculinizing genital gender...

Background: Worldwide, many different surgical procedures and techniques are being used for masculinizing genital gender affirming surgery (gGAS) in transgender and gender diverse (TGD) individuals. Studies reporting on masculinizing gGAS measure and report different outcomes, hindering comparison and thus evidenced-based treatment decision making. This study aims to systematically assess reporting heterogeneity in masculinizing gGAS studies to date. Methods: A systematic review in compliance with the Cochrane Handbook for Systematic Reviews of Interventions was conducted. A multi-database literature search was performed up to September 2023. Clinical studies reporting on outcomes after masculinizing gGAS (i.e. phalloplasty, scrotoplasty, metoidioplasty and coronaplasty) in TGD individuals were included. Data extraction included reported outcomes, their definitions, timing of assessment, measurement instruments used, and primary outcomes for risk of bias evaluation. Results: After screening 922 studies, 87 were included for data extraction. In total, 2077 individual (clinician- and patient reported) outcomes were reported, of which 1026 (49%) were defined. The provided definitions were inconsistent, and the degree of outcome specificity varied. Among the most reported outcomes were neo-urethral fistula (n = 104) and stricture (n = 81), partial (n = 56) and complete (n = 50) flap necrosis, hematoma (n = 36) and, tactile sensitivity in the neo-phallus (n = 36). Measurement instruments were stated for 987 (48%) outcomes, primarily using ad hoc questionnaires. The timing of outcome assessment was specified for 1116 (54%) outcomes, often described as follow-up periods ranging in duration. The primary outcome was declared in 36 (41%) studies. Conclusion: This review demonstrates an extensive use of ambiguous definitions, measurement tools and assessment times following masculinizing gGAS and highlights the necessity for standardization. Adoption of an agreed-upon Core Outcome Set (COS) for masculinizing gGAS could improve the comparability and reliability of research findings and ultimately improve the treatment decision-making process.