In Reply: We agree with Drs van Munster and de Rooij that delirium is likely an important factor in the pathway between acute or critical illness and cognitive decline in older patients. Not only has delirium been shown to be associated with higher mortality, longer length of stay, and greater cost in critically ill patients, a number of studies have demonstrated the association between delirium and long-term cognitive outcomes.1 In addition to the evidence that inflammation may play a role in the pathophysiology of both delirium and dementia, patients with an apolipoprotein E genotype associated with dementia (ApoE4) are at greater risk for delirium when critically ill.2 This also supports a link between mechanisms leading to delirium and those leading to long-term cognitive impairment.
Ehlenbach WJ, Hough CL, Larson EB. Hospitalization and Cognitive Function in Older Adults—Reply. JAMA. 2010;303(21):2137-2138. doi:10.1001/jama.2010.701