Delirium in Acute Elderly Care Unit; Prevalence, Clinical Characteristics, Risk Factors and Prognostic Significance

ABSTRACT

OBJECTIVES: Delirium in elderly patients is thought as transient phenomenon, therefor often unrecognized by physicians. The aim of this study was to investigate incidence of delirium and to determine risk factors for delirium in elderly hospitalized patients METHODS: We studied 172 patients aged 65 years or older who had been admitted to the elderly medical service at geriatrics center from May 2004 to Sep 2004. Delirium was diagnosed by daily interviews according to the DSM-IV criteria for delirium and the CAM(Confusion Assessment Method). Comprehensive geriatric assessment after stabilization was performed by interdisciplinary team including geriatric nurse specialist. The parameters between delirium and non-delirium groups were investigated, that is laboratory variables, dehydration, infection, immobilization, indwelling foley catheter, sleep deprivation, depression, cognitive impairment, ICU stay, comorbidity(stroke, hypertension, diabetes, dementia) RESULTS: Delirium developed in 33 patients(19.2%). Of these, male was 16(26.2% of total male), female was 17(15.3% of total female). Mean onset of delirium just occurred 5 days later. Most of the patients(81.8%) occurred within day 6. Seventy percent of delirious patients were classified as hyperactive type, 18% as mixed type, 12% as hypoactive type. Forty five percent of delirious patients improved within 24hours. Patients who persisted symptom until in-hospital death or discharge were 13(39%). The mean length of stay for delirious patients was longer than non-delirious patients(p<0.05). This study show that 15 factors appeared to predict delirium significantly age greater than 80 years, anemia, hyponatremia, infection, sleep deprivation, immobilization, indwelling foley catheter, cognitive impairment, dementia, hypertension, high BUN, low albumin, low cholesterol, low MMSE, low IADL. CONCLUSION: Delirium was recognized in 19.2% of patients in the elderly hospital setting and was also associated with longer hospital stay and increased mortality. By multiple logistic regression, three independent risk factors for delirium was dementia, sleep deprivation, immobilization.