Diversity and representation within the literature on sexual dysfunction in multiple sclerosis: A systematic review

Introduction: Sexual dysfunction (SD) is a common and distressing symptom for people living with multiple sclerosis (MS). Populations included in existing studies of SD may not fully reflect the diversity of people living with MS, with important implications for wider applicability. We aimed to evaluate reporting of sex, gender identity, sexual orientation, and ethnicity across studies of SD in MS. Methods: A systematic search of four databases was performed. Two independent authors evaluated all papers. Reporting of sex and gender identity, sexual orientation, and ethnicity were recorded. Results: A total of 419 papers were reviewed, and 204 studies with 77,902 participants met the criteria for evaluation. Of 204 studies, 98 (48.0%) included both male and female participants; 78 (38.2%) included females only, and 27 (13.2%) males only. In 19 (9.3%) studies, participants were asked their gender. No studies reported asking a two-step question on sex and gender identity. No studies reported including non-binary patients or gender identities other than male or female. No studies reported including intersex patients. Only 10 (4.9%) studies reported the inclusion of homosexual or bisexual participants, or participants from other sexual minority groups. The overwhelming majority of studies (181; 88.7%) did not report ethnicity or race of participants. Conclusion: Sex, gender identity, sexual orientation, and ethnicity are poorly reported in studies on SD in MS. These variables must be adequately evaluated to ensure research applies across diverse MS patient populations.