Are common delirium assessment tools appropriate for evaluating delirium at the end of life in cancer patients?

Objectives The objectives of this study are to investigate how many advanced cancer patients became unconscious or non‐communicative after pharmacological treatment for delirium, and to explore whether existing delirium assessment tools can successfully evaluate its severity at the end of life. Methods This was a secondary analysis of a registry study that examined the efficacy and safety of antipsychotics for advanced cancer patients with delirium. A total of 818 patients were recruited from 39 specialized palliative care services in Japan. The severity of delirium was measured using the Richmond Agitation‐Sedation Scale‐Palliative care version, the Delirium Rating Scale‐Revised‐98 (DRS‐R‐98), and the Nursing Delirium Screening Scale (Nu‐DESC) on Day 3. Data from 302 patients with motor anxiety with an Agitation Distress Scale score ≥2 on Day 0 were analyzed for this study. The patients were categorized into four treatment response groups: complete response (CR: no agitation and fully communicative), partial response (PR: no/mild agitation and partially communicative), unconscious/non‐communicative (UC), and no change (NC). Results On Day 3, 29 (10%; 95% confidence intervals [CI], 7‐13) and 2 (1%; 95% CI, 0‐2) patients became unconscious and non‐communicative, respectively. Forty‐four patients were categorized as CR, 97 as PR, 31 as UC, and 96 as NC. The scores of the DRS‐R‐98 and Nu‐DESC in the UC group were rated higher than patients in the NC group were. Conclusions: A considerable number of cancer patients with delirium became unconscious or non‐communicative. Existing delirium assessment tools may be inappropriate for measuring the severity of delirium in end‐of‐life.