Opt-out defaults do not increase organ donation rates

To increase organ donation rates, many countries have switched from an opt-in ('explicit consent') default for organ donation to an opt-out ('presumed consent') default. This study sought to determine the extent to which this change in default has led to an increase in the number of deceased individuals who become organ donors.

Longitudinal retrospective analysis.

We conducted a retrospective analysis of within-country longitudinal data to assess the effect of changing the organ donation default policy from opt-in to opt-out. Our analysis focused on the longitudinal deceased donor rates in five countries (Argentina, Chile, Sweden, Uruguay, Wales) that had adopted this change. Using a Bayesian aggregated binomial regression model, we estimated the odds of organ donation within each country over time, as well as the effect of the policy switch.

Switching from an opt-in to an opt-out default did not result in an increase in donation rates when averaged across countries. Moreover, the opt-out default did not lead to even a gradual increase in donations: there was no discernible difference in the linear rate of change of donations after the change in default. Finally, the COVID-19 pandemic was associated with a reduction in the odds of donation across all five countries.

Our longitudinal analysis suggests that changing to an opt-out default does not increase organ donation rates. Unless flanked by investments in healthcare, public awareness campaigns, and efforts to address the concerns of the deceased's relatives, a shift to an opt-out default is unlikely to increase organ donations.