Postoperative patients with the highest delirium severity experienced the greatest rate of cognitive decline, with a dose-response relationship between delirium severity and long-term cognitive decline, according to a study published in the Journal of Alzheimer’s Disease.
“Although the short-term adverse effects of delirium are well-recognised, our results underscore important implications for longer-term prognosis,” said Sarinnapha Vasunilashorn, PhD, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
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.”
The researchers studied a group of 566 patients over a total of 3 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 (CAM). Of these 134 participants, those who displayed the highest severity of delirium later developed the most severe cognitive decline.
No significant cognitive decline was observed for patients with peak CAM-S scores 0 to 2 (-0.17 GCP units/year, 95% confidence interval [CI] -0.35, 0.01). General Cognitive Performance (GCP) scores decreased significantly in the group with peak CAM-S scores 3 to 7 (-0.30 GCP units/year, 95% CI -0.51, -0.09), and decreased almost 3 times faster in the highest delirium severity group (peak CAM-S scores 8-19; -0.82 GCP units/year, 95% CI -1.28, -0.37).
“These results challenge the idea that delirium is reversible with only acute complications,” said Sharon K. Inouye, MD, Hebrew SeniorLife Institute for Aging Research, Boston, Massachusetts. “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. 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.”