Risk of vasovagal reactions among trans versus cisgender whole blood donors

Trans blood donors may be at higher risk of vasovagal reactions (VVRs) if their estimated blood volume is calculated without considering their sex assigned at birth. Yet no studies have addressed this research question. We assessed the rates of VVRs among trans and cisgender blood donors.

This was a cross-sectional study of whole blood donors in Québec, Canada (11 August 2016-25 August 2021). Trans donors were identified if they self-reported their gender transition or following an interview triggered by affirmative answers to questions on recent physician consultations and medication use. The odds of VVR were modelled using logistic regression analyses, adjusting for donor age and status.

Overall, 377,980 donors were included and made 1,799,509 donations: 29 were trans men (mean age ± standard deviation [SD] = 28.6 ± 9.1), 173,464 were cisgender men (mean age ± SD = 42.5 ± 16.2), 13 were trans women (mean age ± SD = 33.7 ± 9.7) and 204,474 were cisgender women (mean age ± SD = 38.7 ± 15.4). There was no statistically significant difference in the odds of VVR (any severity) between trans and cisgender men (odds ratio [OR] [95% confidence interval, CI] = 1.71 [0.88-3.32]) or between trans and cisgender women (OR [95% CI] = 1.33 [0.40-4.40]).

In this study, the risk of VVR was similar among trans and cisgender blood donors.