Thiamine Administration and the Prevalence of Delirium in the Intensive Care Unit: A Retrospective before and after Interventional Study

Background: Thiamine is an essential co-factor for aerobic intracellular respiration, nerve conduction, and muscle contraction. Thiamine deficiency is common in the intensive care unit (ICU). Delirium is a frequent unwanted symptom among critical ill patients. Although the exact cause of ICU-associated delirium is unknown, abnormal nutrition and thiamine deficiency may contribute to the etiology. Objectives: To compare the prevalence of delirium among ICU patients who received thiamine with those who did not and to compare morbidity and mortality. Methods: A retrospective study was conducted among ICU patients admitted 2014-2018. Routine thiamine administration began in 2016. Collected data included patient demographics, medical history, indication for ICU admission, hospital admission times, ventilation days, inotropic therapy, hemodialysis, tracheostomy, 28-day mortality, and need for anti-psychotic therapy. Group A received thiamine, group B did not. All data were statistically analyzed according to type. Results: The study included 930 patients: 465 patients in group A and 465 in group B. At admission and throughout the hospitalization severity of disease parameters was worse in group A compared to group B, including acute physiology and chronic health evaluation (APACHE) score, admission lactate level, ventilation days, inotropic support, renal replacement therapy, tracheostomy, and ICU hospitalization. Group A had fewer delirium events without difference of maximal delirium score. No difference in mortality rate was observed. Conclusions: Thiamine administration was associated with lower delirium prevalence despite longer ICU admission times and higher disease severity parameters at admission and during ICU stay.