The Relationship of Hemoglobin Levels, Delirium and Cognitive Status in Hospitalized Geriatric Patients: Results from...

Delirium is a frequent clinical complication in geriatric patients admitted to the hospital, because of the simultaneous presence and synergistic effect of predisposing and precipitating factors. Also anaemia is a common concern in geriatric population. The aim of this study was to investigate the association between anaemia (precipitating factor) and delirium in a sample of Italian older hospitalized patients with different degree of cognitive impairment (predisposing factor).

Cross-sectional analysis of 1069 participants enrolled in the CRIME study, with assessment of hemoglobin levels at hospital admission.

Delirium was assessed using DSM-IV criteria, whereas cognitive status was categorized as dementia, cognitive impairment or normal, according to clinical history, specific treatment and MMSE score. Anaemia was defined according to sex-specific WHO criteria. The association of hemoglobin levels and delirium was investigated with multivariable logistic regression models.

Mean age of study participants was 81.4±7.2 years, 52.2% had prevalent anaemia, 6.1% had delirium. According to cognitive status 20.8% had dementia and 40.9% had cognitive impairment. Overall there was no association between anaemia and delirium. However, among patients with cognitive impairment (MMSE <24, no dementia) anaemia was significantly associated with the likelihood of delirium (p<0.006). Multivariate logistic regression analysis, adjusted for potential confounders, showed in these patients a graded increased risk of delirium according to anaemia severity with an almost six-fold increased risk of delirium in moderate-severe anaemia (OR 5.95, 95% CI:1.15-30.73).

In older patients with cognitive impairment moderate-severe anaemia is independently associated with the likelihood of delirium. Further studies should investigate if anaemia correction would translate in delirium risk reduction.