Researchers from Harvard Medical School and Hebrew SeniorLife Institute for Aging Research, in collaboration with scientists from Beth Israel Deaconess Medical Center and Brown University, have found increasing evidence that the level of delirium in postsurgical patients is associated with the level of later cognitive decline in those same patients. Findings from this study appear in the Journal of Alzheimer’s Disease.
Delirium is a common, serious and often fatal disorder affecting as many as 50 percent of older people during the course of surgery or hospitalization and costing more than $164 billion per year. Delirium has been associated with increased functional decline, prolonged hospital stays, higher rates of institutionalization and greater mortality. Delirium is also associated with a significant decline in cognitive ability. The authors of this study have found that for those patients who display postsurgical delirium and then develop later cognitive impairment, the severity of cognitive impairment has a direct correlation to the severity of prior delirium.
“Although the short-term adverse affects of delirium are well-recognized, our results underscore important implications for longer-term prognosis,” said Sarinnapha Vasunilashorn, HMS instructor in medicine at Beth Israel Deaconess and contributing author on the study. “The findings suggest that for patients with moderate to severe delirium, the decline in cognition may be both substantial and long-term, and most notably, it exceeds the rate of decline observed in patients with dementia.”
Researchers studied a group of 566 patients over a total of three years. Before their surgeries, none of these patients displayed signs of dementia. After surgery, a total of 134 participants displayed signs of delirium based on their evaluations using the Confusion Assessment Method. Of these 134 participants, those who displayed the highest severity of delirium later developed the most severe cognitive decline.
“These results challenge the idea that delirium is reversible with only acute complications. Though delirium generally subsides after a period of time, it appears to have lasting effects, the severity of which are related to the severity of the delirium itself,” said Sharon Inouye, HMS professor of medicine and director of the Aging Brain Center at Hebrew SeniorLife’s Institute for Aging Research and senior author on the study. “This work suggests the need to target patients with high-delirium severity for strategies to prevent progressive cognitive decline as they are at increased risk for dementia.”