First of all, let it be known far and wide that simply having an advance directive does NO good. It doesn't impact the care you do or don't receive, and most of the time, it can't even be located, let alone honored.
What DOES make a significant impact is HAVING THE DISCUSSION. Talking with a knowledgeable expert about what options are available, the pros and cons, risks and benefits, likely outcomes, etc. Talking with your physician and your family about your values. This is what advance care planning is. Advance directives are the documents that result from the planning. (And just a personal plug, if you have a Living Will, you might as well toss it. It is very limited and not helpful. Get a Power of Attorney for Healthcare.)
The discussion needs to happen with the physician, but what physician these days has the time to go in depth about these issues? So the current state is to ask patients to "sign this form", and we call it "informed consent". If you've ever had a medical procedure, you have experienced this. Tell me that your doctor truly spent the time to inform you of the issues, and then asked permission. It just doesn't happen.
But I digress. The issue again is about choices. I saw a dying young man recently who had pain written all over his face. He has been on multiple regimens for his pain, with varying degrees of success. Clearly, what he is doing now isn't working. Yet, each time I tried to discuss another option with him, he refused. It wasn't necessarily fear of drowsiness from strong pain relievers, or not wanting to take any more pills. For this young man, it was existential. He had been healthy, and could not understand why this had happened to him. He was struggling with issues of meaning and spirituality, and though I tried to describe for him how he might be better able to deal with those issues if his pain was less severe (and the converse is also true), he would have none of it. I knew I could help him feel better. He chose not to. Who am I to judge?
Another recent encounter was with an elderly man whose family did NOT want to tell him how sick he was, let alone that he was on hospice. This man was alert, and knew what was going on around him. Yet, when I specifically asked him how much he wanted to know about what was happening to his health, he deferred to his family. He wasn't trying to avoid it and wasn't in denial. He knew how bad his health had been the last few years. But this was his informed choice, to defer the discussion to those he trusted.
Cultural issues abound. An Asian family wanted me to not talk about ANYTHING negative around their dying mother. They truly believed they would witness a miracle. They were open to palliative treatment, but not to talking about dying.
Lest anyone get the wrong idea, I do NOT in ANY WAY support euthanasia or physician assisted suicide. These are morally reprehensible to me. That is not the choice I am talking about here. But for so long, we have tried to treat chronic progressive disease the same way we treat acute life threatening illness, we have forgotten to note the differences. We can and should continue to use aggressive therapies when appropriate. But who is the one who should really have the final say as to what appropriate is? A patient who doesn't know all the options cannot meaningfully participate in this discussion with the expert physician. Docs need to get over themselves and start being honest with patients. We don't take away their hope, even if they are terminal. The disease did that. We are helping them prepare, and this benefits everyone. And guess what? It turns out to cost less according to all the studies out there. We should do the advance care planning because it is the right thing to do, and happens to have financial benefit, and keep the financial issues secondary, where they belong. Then we won't have all the debates and misinformation about Death Panels. Patients will be well cared for, and when their lives are ending, they can be comfortable, and surrounded by love.