Thiamine Deficiency Is Common and Underrecognized in Emergency Department Oncology Patients.

: Wernicke's encephalopathy can occur in oncology patients independent of alcohol use, likely resulting from poor dietary thiamine intake. High metabolic demands, such as those in acute illnesses seen in the emergency department (ED), can exacerbate thiamine deficiency. In this study, our objective was to assess the incidence of thiamine deficiency in ED oncology patients, which could lead to Wernicke's encephalopathy or other thiamine deficiency disorders if left untreated. : This was a single-center prospective cohort study. We included patients with acute illness and a history of active cancer management in the ED of a large, urban hospital. We also included age and sex-matched control patients with no history of cancer who sought ED care. We excluded patients with a history of alcohol use or parenteral thiamine administration before enrollment. We recorded whole blood thiamine levels to measure total body thiamine stores and collected data on clinical variables, thiamine treatment, and adverse events. : In total, 87 oncology and 71 control patients were included in the study. The mean age was 62.1 ± 13.7 and 58.9 ± 12.6 years, respectively, and 48% of oncology vs. 55% of control participants were female. The most common cancers represented were colon (23%), lung (25%), prostate (10%), and breast (9%). Thiamine deficiency was significantly higher in ED oncology patients (25, 28.7%) compared to controls (6, 8.5%), odds ratio 4.4 (95% CI 1.7-11.4). None of the oncology patients with deficiency received thiamine treatment in the ED. : Our findings suggest that thiamine deficiency is prevalent in acutely ill oncology patients, yet rarely treated in the ED.