Sharing preferences for end of life care, known as advance care planning, may be linked to longer survival in terminally ill patients, suggests the first study of its kind, published online in the journal BMJ Supportive & Palliative Care.
Advance care planning enables adults to discuss wishes and priorities for their care, including stopping treatment to prolong life, when they are no longer able to do so.
But it's not known what impact this might have on survival in patients who are terminally ill.
The researchers used data from a previously published randomised controlled trial, which aimed to find out if advance care planning had any impact on meeting terminally ill patients' preferences for place of death.
This involved tracking the date of death for 205 terminally ill patients, 102 of whom had had a conversation about their preferences for end of life care with a doctor, and 103 of whom hadn't.
Around half the patients in each of the groups had advanced cancer, and half had been terminally ill with heart and lung conditions.
Additional analysis of these data showed that there was a difference in survival after a year of monitoring between those who had had this type of conversation and those who hadn't.
Nearly three out of four of those (73%) of those who had done so were alive after a year compared with over half (57%) of those who hadn't.
While there was no significant difference in survival between terminally ill cancer patients who had and hadn't had an advance care planning conversation, there was between those with other types of terminal illness, the analysis showed.
Among this group, nine out of 10 (90%) of those who had done so were alive after a year, compared with two thirds (67%) of those who hadn't.
By way of a possible explanation for this finding, the researchers suggest that this type of conversation helps these patients better understand the life-limiting nature of their illness.
This may change their views about having treatment that prolongs life, such as steroids, which, paradoxically, have been associated with a heightened risk of death and other illness - at least among those with serious lung disease, say the researchers.
The researchers didn't set out to look at the potential impact of advance care planning on survival, and this finding was a by-product of their research in a relatively small number of people, so requires further study, they say.
"[Advance care planning] was associated with a significantly improved survival among terminally ill patients, primarily [those] with non-cancer diseases. However, the analysis was explorative, and the association must be investigated further before drawing any firm conclusion," they conclude.