New research from Harvard Medical School researchers at Hebrew SeniorLife suggests that delirium - the most common postoperative complication in older adults - is associated with a 40 percent faster rate of cognitive decline in those who develop delirium over those who do not.
- By MICHAEL CHMURA | Hebrew SeniorLife
The study, which includes co-authors from HMS, the Warren Alpert Medical School of Brown University, and the University of Maryland, was published March 20 in JAMA Internal Medicine.
"This study has the longest follow-up period of any study examining persons with delirium following surgery," said Sharon Inouye, HMS professor of medicine at Hebrew SeniorLife, the study's senior author and principal investigator.
"While future studies are needed, this study raises the possibility that delirium may predispose to permanent cognitive decline and potentially dementia. This highlights the importance of delirium prevention to preserve brain health in older adults who undergo surgery," she said.
Inouye is also director of the Aging Brain Center at the Hinda and Arthur Marcus Institute for Aging Research.
"Delirium is associated with faster cognitive decline," said first author Zachary Kunicki of the Warren Alpert Medical School of Brown University. "Whether delirium causes this faster rate of decline or is simply a marker of those who are at risk of experiencing faster rates of decline is still to be determined."
The Successful Aging after Elective Surgery Study (SAGES) has followed a cohort of 560 adults ages 70 and older, measuring their cognition every six months for 36 months, then annually for up to six years.
Using a detailed cognitive battery of 11 different tests, the researchers found that cognitive changes after surgery are complex and that delirium influences every timepoint.
The average cognitive changes seen after surgery include an abrupt drop at one month after surgery, an increase at two months after surgery, a stable period from six to 30 months after surgery, and then steady decline three to six years after surgery.
Delirium is associated with a sharper drop at one month, greater recovery at two months, and faster decline in all time periods from six months to six years.
The results suggest that either delirium itself may contribute to cognitive decline after surgery or that delirium may serve to identify those at risk for more rapid cognitive decline in the future.
Further research is needed to examine whether either or both hypotheses best explain the relationship between delirium and cognitive decline.
Authorship, funding, disclosures
Co-authors included Richard Jones, co-senior author; Long Ngo, Edward Marcantonio, Douglas Tommet, Yi Feng, Tamara Fong, Eva Schmitt, and Thomas Travison.
The study was supported by NIH grants P01AG031720 (S.K.I.), R33AG071744 (S.K.I./R.N.J.), R01AG044518 (S.K.I./R.N.J.) from the National Institute on Aging.
