Changes in the quantity and level of evidence of palliative and hospice care literature: the last century.

PURPOSE: To objectively quantify the literature and the clinical trial basis for palliative and hospice practice given a perception that its evidence base is not well developed.
METHODS: Using Ovid Medline, the study looked at cumulative and absolute numbers of articles in the general medical literature and the palliative and hospice care literature. The same comparisons were made exploring clinical trials from 1902 to 2005. Data were collated in five year groups from 1970 onward using a highly specific search phrase.
RESULTS: The proportion of all Ovid Medline publications relating to palliative and hospice care rose from 0.08% in 1970 to 0.38% of the literature in 2005. In the same time, clinical trials increased from 0.96% to 7.22% of the palliative care literature published. By 2005, one in every 122 clinical trials published in the literature as a whole was in palliative or hospice care. The rate of growth in palliative care clinical trials as a proportion of all palliative and hospice publications was on average 1.4 times greater than in the corresponding general literature. More than one half of these studies were reported in just 43 journals, most of which were not specialist palliative and hospice care journals. DISCUSSION: Given the diversity of journals in which clinical studies related to hospice and palliative care appear, there is a key challenge for clinicians in finding ways that will allow currency of practice in a broad and rapidly changing field.