Underrecognition of Delirium in Palliative Care: A Retrospective Comparison Between Cancer and Noncancer Patient Populations

Background: Delirium is associated with high mortality and substantial patient distress; therefore, early identification and management are crucial. Among patients with cancer receiving palliative care, delirium is highly prevalent yet often underrecognized by attending physicians. Recently, palliative care for patients with noncancer conditions has gained attention. Nonetheless, the prevalence of delirium and the extent of physician awareness in this population remain unclear. This study aimed to clarify these aspects in noncancer patient populations to raise awareness among physicians and provide insights to improve palliative care delivery. Methods: We retrospectively reviewed 1540 inpatients receiving palliative care at a university hospital in Japan between January 2018 and December 2023. Psychiatric diagnoses, referral reasons, physical diagnoses, and demographic information were analyzed. Results: In the noncancer group, the number of annual referrals to palliative care increased during the study period (from 7 to 66). Both the cancer and noncancer groups were commonly referred for pain, dyspnea, anxiety, insomnia, and delirium. Compared with the cancer group, the noncancer group was more likely to receive a psychiatric diagnosis (45.7% vs. 57.6%) and had a higher prevalence of delirium (12.9% vs. 21.5%). In the noncancer group, the proportion of referrals citing psychiatric symptoms was higher (38.5% vs. 54.2%), whereas the frequency of delirium underrecognition was comparable to that in the cancer group (59.6% vs. 71.0%). Conclusion: Underrecognition of delirium in palliative care settings is a common issue in both cancer and noncancer patient populations. Enhancing physician awareness may improve palliative care quality in these populations.