Incidence, prevalence and risk factors for delirium in elderly admitted to a coronary care unit

Abstract

Aim: This study attempted to assess the incidence, prevalence, risk factors and outcome of delirium in elderly (≥60 years) patients admitted to a coronary care unit. Materials and Methods: Confusion Assessment Method for Intensive Care Unit (CAM-ICU) was used to screen the patients for delirium and those found to have delirium on CAM-ICU were subjected to a detailed evaluation by a psychiatrist to confirm the diagnosis of delirium. Additionally risk factors were assessed by using a checklist and outcome was determined. Results: One hundred and fifty two patients were evaluated for delirium. Of these, 37 (24.34%) patients had delirium at the first assessment (i.e. within 24 hours of admission in CCU) and were classified as ′prevalence cases′ of delirium. Fifteen cases (13.04%) developed delirium after 24 hours of CCU stay and were considered as ′incidence cases′ of delirium. Among the various risk factors studied, factors which were identified as predictors of delirium in binary logistic regression analysis were hypokalemia, Sequential Organ Failure Assessment (SOFA) score, use of warfarin, frusemide, ranitidine, benzodiazepine, opioids, steroids, more than 4/5 medications, presence of sepsis, cardiogenic shock, having undergone coronary artery bypass grafting, left ventricular ejection fraction <30, higher age, presence of uncontrolled diabetes mellitus and presence of congestive cardiac failure. Of the 52 patients who developed delirium, 10 (19.2%) died during their hospital stay, this was significantly higher than the mortality rate (1%) seen in the non-delirium group. Conclusions: In coronary care units, delirium is a common entity in elderly and is predicted by the presence of modifiable risk factors. Delirium is also associated with increased mortality.

Keywords

• Delirium
• Elderly
• Cardiac Illness