Hospitalized patients who experience delirium—an acute state of disorientation—have an elevated risk of long-term cognitive decline, according to a meta-analysis published today in JAMA Neurology. The risk was similar regardless of whether the patients were recovering from surgery or other serious conditions, such as sepsis or respiratory failure.
“From a public health standpoint, delirium represents a clear target to improve population health,” wrote Terry Goldberg, Ph.D., of Columbia University Irving Medical Center and colleagues. “Delirium is robustly associated with increases in mortality and, as shown here, long-term cognitive decline.”
The investigators combined data from clinical studies that looked at the rates of dementia or other objectively measured cognitive problems in patients at least three months after an episode of delirium. They identified 24 studies encompassing 3,562 patients who experienced delirium and 6,987 patients who did not experience delirium. (The mean age of the patients included in the meta-analysis was 75 years.)
Patients who had experienced delirium were 2.3 times as likely to show cognitive decline three months later compared with patients who had not experienced delirium. The circumstances of the delirium (following anesthesia, trauma, infection, and so on) did not affect the odds of future cognitive decline. This suggests that the underlying mechanisms of delirium may be similar and possibly associated with inflammatory processes common to both surgical and nonsurgical contexts, the investigators noted.
“While our analyses were consistent with a causal hypothesis, causality cannot be confirmed because these studies were designed as observational in demonstrating associations,” Goldberg and colleagues wrote. “Findings based on prospective randomized clinical trials, albeit difficult to implement, might help to resolve this issue.”