Healthy or not, here advanced medical directives come.

Just over one-third of adults in the United States have advanced directives for medical care, according to new research findings. These documents are important when they become seriously ill or incapable of making their own health care decisions. Yet the low figure suggests more needs to be done.

“This is a comprehensive national snapshot of the most widely promoted tool for end-of-life care planning and suggests that there is plenty of room to increase its reach,” senior study author Dr. Katherine Courtright told Reuters Health. She works with the Fostering Improvement in End-of-Life Decision Science Program at the University of Pennsylvania.

Courtright and her fellow researchers analyzed studies published between 2000 and 2015 about advanced medical directive completion across the country. The analysis showed that 36.7% of adults completed advanced medical directives of some kind.

– 29% had living wills

– 33% had health care powers of attorney

– 32% had undefined advanced directives

Older patients and those in hospice or palliative care were more likely to have advanced medical directives, as well as those with cognitive impairment like dementia. End-of-life care documents were least common among those with HIV/AIDS, according to the findings.

“It was somewhat surprising how much the completion rate varied based on age, patient location and diagnosis, yet even among those with the highest completion rates, nearly half still hadn’t completed them,” Courtright told Reuters Health.

Advanced medical directives signed by those with chronic illness and those considered healthy were quite similar, at 38.2% and 32.7%, respectively.

“The fact that only a third of sick patients are expressing their end-of-life wishes means we’re in trouble,” said Dr. Melissa Wachterman, of Harvard Medical School, who wasn’t involved in the study. “Everybody should have this conversation because our values and preferences change over time. A healthy 72-year-old may say she wants a breathing tube, but that choice may change.”

Advocates and researchers involved in advanced care planning want to find ways to break down barriers to completing directives. This may involve removing legal jargon, changing the reading level and revising medical terms used.

But at the end of the day, a completed advanced medical directive is only as good as conversations and understanding around them.

“Some people do fill out these forms with families or lawyers, and then the forms sit in the dusty recesses of a back drawer – they are not available or shared with family and friends, especially before they are needed,” Dr. Rebecca Sudore told Reuters. She is with the University of California, San Francisco and wasn’t involved in the study.