Association Between Low Omega-6 Polyunsaturated Fatty Acid Levels and the Development of Delirium in the Coronary Intensive Care Unit

<b>Background:</b> Delirium is frequently observed in patients admitted to the intensive care unit, and is associated with mortality and morbidity. Although several studies have reported an association between polyunsaturated fatty acids (PUFAs) and cognitive disorders, the association between PUFA levels and development of delirium in patients with acute cardiovascular disease remains unknown. <b>Objective:</b> This study aimed to clarify the association between PUFA levels and development of delirium in the coronary intensive care unit (CICU). <b>Methods:</b> We enrolled 590 consecutive patients (mean age, 70 ± 14 years) admitted to the CICU of Juntendo University Hospital. Fasting serum PUFA levels were measured within 24 h of admission. Delta-5 desaturase activity was estimated as the ratio of arachidonic acid (AA) to dihomo-gamma-linolenic acid (DGLA). Furthermore, delirium was defined as patients having a delirium score of ≥4 using the Intensive Care Delirium Screening Checklist. <b>Results:</b> Delirium was observed in 55 patients. DGLA levels were significantly lower, and delta-5 desaturase activity was significantly higher in patients with delirium than in those without delirium (both <i>p</i> < 0.001). Conversely, AA alone and omega-3 PUFAs did not differ between the groups. Additionally, DGLA and AA levels, but not omega-3 PUFA levels, were negatively associated; delta-5 desaturase activity was positively associated with the delirium score (both <i>p</i> < 0.001). The duration of delirium was significantly associated with DGLA and AA levels (<i>p</i> = 0.001 and <i>p</i> = 0.004, respectively). Moreover, multivariate analysis showed that decreased DGLA and increased delta-5 desaturase activity remained significant predictors of delirium. <b>Conclusions:</b> Low omega-6 PUFA levels and high delta-5 desaturase activity on admission were significantly associated with the development of delirium in the CICU, indicating that the evaluation of low omega-6 PUFA levels and related enzymes may identify patients at a high risk of developing delirium.