Delirium is a common, serious, often fatal disorder that affects as many as 50 percent of older people during the course of surgery or hospitalization. Yet, despite delirium’s incidence among elderly hospitalized patients, its relationship to long-term cognitive decline has not been well explored.
In the July 2016 issue of Alzheimer’s & Dementia, however, researchers from HMS and Hebrew SeniorLife Institute for Aging Research report that there is increasing evidence that delirium in older surgical patients may be associated with such cognitive decline. The study, conducted in collaboration with scientists at Beth Israel Deaconess Medical Center, Brown University, and Northeastern University, examined the trajectory of short-term and long-term cognitive decline in patients who experienced post-surgical delirium.
The study involved 560 participants, each age 70 or older and each without previous signs of dementia, who were scheduled to undergo surgery with an anticipated hospital stay of three days or more.
Over 36 months following their surgeries, 134 patients experienced delirium. Those who experienced delirium as well as those who did not showed a significant cognitive decline at one month, a recovery above baseline at two months, then a gradual decline during the following 34 months. Yet those who had experienced delirium showed a significantly greater decline at one month compared to those without delirium. Although they too recovered at two months, the patients who experienced delirium had a more significant decline after the two-month mark than patients who did not experience delirium.
Beyond two months, both groups declined on average, but the delirium group declined significantly more. When researchers compared changes from baseline to 36 months, there was no significant change in the group that did not experience delirium, but there was a marked decline in the group that did.