Prevalence, course and factors associated with delirium in elderly patients with advanced cancer: a longitudinal observational study

The aim of this study was to investigate the prevalence of delirium on admission, the course of delirium during a 2-week period after admission and factors associated with delirium on admission, among elderly patients with advanced cancer. Patients aged ≥ 65 years with incurable lung or gastroenterological cancer and the Eastern Cooperative Oncology Group Performance Status 2 or greater were continuously sampled after admission to a university hospital. Participants were evaluated for DSM-IV-TR delirium by trained psychiatrists and the delirium subtype was assessed using the Delirium Motor Subtype Scale within 4 days after admission and again 2 weeks later. In addition, we assessed associated factors with delirium on admission. Among 73 eligible patients, complete data were available from 61 on admission and 49 after 2 weeks. Twenty-six patients (43%) met delirium criteria on admission (hypoactive: 58%, unspecified: 35%, hyperactive: 4%, mixed: 4%). Of these, 19 (73%) remained delirious 2 weeks later. Of 35 patients without delirium on admission, 21 (60%) remained delirium-free 2 weeks later and 7(20%) became delirious. Overall, 33/61 (54%) developed delirium at some point during the study. Patients receiving steroids at admission were more likely to have delirium (odds ratio = 5.0; 95% confidence interval = 1.5-16). Given the high prevalence of the delirium, all patients with advanced cancer should be screened for delirium both on admission and regularly thereafter. In addition, medical staff should be aware that steroid use on admission is an additional indicator of elevated risk for delirium.