Delirium occurs frequently but appears underdiagnosed in patients with advanced cancer who presented in the ED, according to the results of a randomized observational study.
Further, the incidence of delirium was comparable among younger and older patients, suggesting all patients with advanced cancer are at risk.
“We found evidence of delirium in one of every 10 patients with advanced cancer who are treated in the ED,” Knox H. Todd, MD, MPH, FACEP, professor and chair of emergency medicine at The University of Texas MD Anderson Cancer Center, said in a press release. “Given that we could only study patients who were able to give consent to enter our study, even 10% is likely to be a low estimate.”
Although delirium is the most frequent neuropsychiatric adverse event among patients with advanced cancer, its incidence among patients presenting in the ED was unknown.
Todd and colleagues identified 624 patients with advanced cancers who presented at the MD Anderson Cancer Center ED, of whom 241 (median age, 61.8 years; range, 19-89) gave consent to participate in this study.
A trained research assistant reviewed the medical records of each patient, then asked the assigned attending physician if the patient appeared stable enough to be approached for questioning.
The research assistant administered the Confusion Assessment Method (CAM) to screen for delirium. A positive result of this assessment (score of 3 or 4) indicates the presence of acute onset and fluctuating course and inattention, as well as either disorganized thinking or altered level of consciousness.
Researchers also used the Memorial Delirium Assessment Scale (MDAS) to determine the severity of delirium (mild, ≤ 15; moderate, 16-22; severe, ≥ 23).
Twenty-two patients were considered delirious by both assessments; however, an additional 22 patients had negative CAM results but positive MDAS scores.
CAM testing determined that 9.1% (95% CI, 5.47-12.71) of patients experienced delirium, with scores of 3 (n = 10) or 4 (n = 12).
Patients with positive CAM scores had an MDAS range between 9 and 21; CAM–negative patients who tested positive for delirium by MDAS had scores ranging between 7 and 13. Eighty-two percent (n = 18) of CAM–positive patients had mild delirium and 18% (n = 4) had moderate delirium.
ED physicians identified delirium in 15 patients, 13 of whom tested positive for delirium by CAM (59%). Two patients judged to be delirious by physicians were false-positives, and the physicians missed delirium in nine patients (41%) who tested positive.
Patient characteristics for those found to have delirium did not significantly differ with regard to age (< 65, n = 12; ≥ 65, 10), sex, race or ethnicity, marital status or employment status. However, delirious patients tended to have a poorer ECOG performance status (P < .0001).
Medications was the main cause of delirium in 91% (n = 20) of patients; other causes included brain metastases, chemotherapy, fever or infection, and organ failure.
Study limitations included the use of a single ED site, the relatively small number of patients and the potential bias introduced by unblinding physicians to their patients’ delirium status.
Further, the study excluded patients who appeared unstable, had dementia or refused to participate, which likely introduced selection bias.
“Further research is needed to identify the optimal screening tool for delirium in the ED,” Todd and colleagues wrote. – by Cameron Kelsall
Disclosure: The researchers report no relevant financial disclosures.