Developing Postoperative Delirium is Associated with a Faster Rate of Cognitive Decline

BOSTON -- Research published today in JAMA Internal Medicine finds that developing postoperative delirium is associated with a 40% faster rate of cognitive decline over those who do not develop delirium.

“Delirium is associated with faster cognitive decline,” said Zachary J. Kunicki, Ph.D., M.S., M.P.H., assistant professor at the Warren Alpert Medical School of Brown University, and the first author.  “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.”

“This study has the longest follow-up period of any study examining persons with delirium following surgery,” said Sharon K. Inouye, M.D., M.P.H., director of the Aging Brain Center, Hinda and Arthur Marcus Institute for Aging Research, and senior author and principal investigator on the work.  “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.

Delirium is the most common post-operative complication in older adults and is associated with poor outcomes, including long-term cognitive decline and incident dementia.

Richard N. Jones, Sc.D., Warren Alpert Medical School of Brown University, is co-senior author of the article, “Six-year cognitive trajectory in older adults following major surgery and delirium.” Inouye is the overall principal investigator of the SAGES Study (NIH grant No. P01AG031720) that funded this long-term observational study.

The SAGES cohort has followed 560 older adults (age 70 and older), measuring their cognition every 6 months for 36 months, then annually afterwards for up to 6 years. Using a detailed cognitive testing battery, comprised of 11 different tests, we 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 6-30 months after surgery, and then steady decline from 3-6 years after surgery. Delirium is associated with a sharper drop at 1 month, greater recovery at 2 months, and faster decline in all time periods from 6 months to 6 years, respectively. 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 future more rapid cognitive decline. Future research will be needed to examine whether either or both of these hypotheses best explain the relationship between delirium and cognitive decline.

Collaborating institutions are Warren Alpert Medical School of Brown University; Beth Israel Deaconess Medical Center; Harvard Medical School; and the University of Maryland.

The study was supported by grants no. P01AG031720 (S.K.I.), R33AG071744 (S.K.I./R.N.J.), R01AG044518 (S.K.I./R.N.J.) from the National Institute on Aging.

About the Hinda and Arthur Marcus Institute for Aging Research
Scientists at the Marcus Institute seek to transform the human experience of aging by conducting research that will ensure a life of health, dignity, and productivity into advanced age. The Marcus Institute carries out rigorous studies that discover the mechanisms of age-related disease and disability; lead to the prevention, treatment, and cure of disease; advance the standard of care for older people; and inform public decision-making.

About Hebrew SeniorLife
Hebrew SeniorLife, an affiliate of Harvard Medical School, was founded in 1903 and today is a national leader dedicated to empowering seniors to live their best lives. Hebrew SeniorLife cares for more than 3,000 seniors a day across six campuses throughout Greater Boston. Locations include: Hebrew Rehabilitation Center-Boston and Hebrew Rehabilitation Center-NewBridge in Dedham; NewBridge on the Charles, Dedham; Orchard Cove, Canton; Simon C. Fireman Community, Randolph; Center Communities of Brookline; and Jack Satter House, Revere. Hebrew SeniorLife also trains more than 1,000 future health care professionals each year, and conducts influential research into aging at the Hinda and Arthur Marcus Institute for Aging Research, which has a robust research portfolio whose NIH funding in 2021 places it in the top 10% of NIH-funded institutions. For more information about Hebrew SeniorLife, visit our website or follow us on our blog, Facebook, Instagram, Twitter, and LinkedIn.

About the Warren Alpert Medical School
The Warren Alpert Medical School is the medical school of Brown University, located in Providence, Rhode Island, United States. Established in 1811, the school was among the first in the nation to offer academic medical education. Today, Alpert Medical School is a component of Brown’s Division of Biology and Medicine, which also includes the Program in Biology. (A third component of the Division, the Program in Public Health, became the Brown University School of Public Health on July 1, 2013.) Together with the Medical School’s seven affiliated teaching hospitals, the Division attracts over $240 million in external research funding per year. The fourth most selective medical school in the United States, Alpert Medical School earned rankings of twenty-fourth for primary care education and thirty-first for research in the 2014 U.S. News & World Report rankings. Graduates of Alpert Medical School are accepted into competitive residency programs and leading medical centers.