Identification of patients at risk for delirium on a medical oncology hospital ward

130 Background: Delirium is a distressing experience for patients with cancer. Incidence rates of delirium vary between 5 and 88 percent. We studied the incidence of delirium on our medical oncology ward, along with its predisposing and precipitating factors, in order to identify patients who may benefit from screening and early interventions. Methods: We evaluated patients admitted to our medical oncology ward between January 2011 and June 2012 for delirium. In this period a screening program with the Delirium Observation Screening Scale was initiated. Risk factors for delirium were extracted from the patient’s chart. We developed a prediction model to identify patients who are at risk to develop delirium and optimized this model with a cohort of patients with a delirium diagnosed between June 2012 and September 2013. Results: 1,733 admittances of 574 individual patients were recorded in the study period. Sixty episodes of delirium were identified in 52 patients. The patients had a mean age of 60 years, and most patients (70%) had advanced cancer. The most prevalent predisposing and precipitating factors were age >70, drug intoxication, infection and metabolic imbalances (abnormalities in sodium, potassium, calcium, albumin or glucose levels), which were present in 21, 25, 22, and 18 percent, respectively. The prediction model revealed that patients who were electively admitted had a very low risk to develop delirium (1%), but patients admitted for an emergency with at least one metabolic abnormality, such as hyperkalemia, were at high risk for developing a delirium (delirium risk 33%). Conclusions: Based on our analyses for risk factors of delirium, we developed a new prediction model for the risk for delirium in patients with cancer admitted to an oncology ward that may be used for targeted screening and to study preventive therapy in order to improve their quality of life.