Only about one-third of US adults have completed an advance directive, despite the evidence that having one substantially improves the alignment between what patients want at end of life and what they receive. Silveira and colleagues’ 2010 NEJM analysis of 3,746 decedents in the Health and Retirement Study found that those with advance directives were significantly more likely to receive care consistent with their stated wishes, and fewer than 5% of bereaved family members reported that the document caused conflict or distress. The Detering 2010 BMJ randomised trial of advance care planning in 309 elderly hospital inpatients found that family members of patients without any ACP were twice as likely to show clinically significant anxiety, depression, or PTSD within three months of the death — 29% versus 15%.
What makes the deferral decision costly is that it often becomes permanent. The 64% of Americans who die without a documented advance directive did not all consciously decide to defer — many simply never got around to it. The legal infrastructure for advance directives in the US involves 50 different state forms with varying requirements for witnesses, notarization, and scope; completing an AD in one state and dying in another creates enforcement uncertainty. The evidence on when advance directives are consulted and followed is also imperfect: documents that exist in filing cabinets but not in electronic health records have limited practical effect. The completion decision and the accessibility decision are not the same.
The Detering RCT’s setting — elderly hospital inpatients in Australia, mean age 80 — is different from middle-age preventive ACP completion. The benefit of completing an AD at 45 rather than 79 likely operates through a different mechanism: it forces a conversation about values and preferences that becomes more difficult when illness has already begun, it reduces the burden on surrogates who must guess at preferences without guidance, and it avoids the scenario where capacity is lost before the conversation can be had. Fewer than 5% of AD completers across the literature show any documented regret from having completed one. The main cost of acting early is administrative; the main cost of waiting is the non-trivial probability that waiting becomes permanent.