Sex and Gender Considerations in Transplant Research: A Scoping Review

In response to the promotion of sex and gender integration in health-related research, we conducted a scoping review evaluating to what extent sex and gender were considered in the transplantation literature.

We searched Medline and Embase for manuscripts published between January 1946 and October 2016. Two reviewers independently selected manuscripts describing clinical research on stem cells, tissues, or solid organ transplantation with ≥20 participants, which mentioned "sex" and/or "gender" in the title or abstract. For each eligible manuscript, 2 of 5 reviewers extracted data on study design, population (transplant candidates, recipients, donors), transplant type, and study outcomes. We evaluated whether the terms "sex" and "gender" were applied according to their correct definitions and how these variables were handled at the level of study design and analysis.

Of 7565 search results, 2107 manuscripts met the inclusion criteria. Sex and gender were applied interchangeably in more than half of the studies (57.5%). Rarely were sex or gender, when applied correctly, considered in the primary study question (13.3% and 25.0%, respectively). The majority of the studies considered these variables as confounders (74.6% for sex and 68.2% for gender), and a minority considered them as effect measure modifiers (2.8% for sex and 5.0% for gender).

Despite a growing awareness of the need to integrate sex and gender in health research, education is required to ensure accurate and meaningful consideration of these concepts. We outline strategies for integrating sex and gender in allotransplantation and donation research during study design and analysis.