Yes. That's an excellent question.
The data is extremely clear about it. Opt-in has about a 20% uptake with patients. Opt-out has about 80% or 90% success in getting the data. If you're going to do the study.... I wouldn't even suggest doing the study if it's opt-in, because they fail.
One of the advantages of our waiting for 30 years to get this started is that there is lots of published data out there from other countries that have done all the trial and error. There are some excellent studies on the other registries around the world, which we can learn from. Germany and Italy have taken the approach of making the registry mandatory. It's not even opt-out. It's mandatory for the surgeons and patients, which is something to discuss.
I think patient confidentiality is always important in any database of patient-related data. In the case of having a national registry, it would be paramount to the success of the registry. Obviously, clinical data, particularly with this type of subject, which is very sensitive.... A lot of people don't want to have that data out there. You would have to mandate very rigid patient confidentiality parameters in addition to making it opt-out.