Delirium’s cognitive toll persists long after surgery

Clinical Takeaway: Older adults who develop postoperative delirium appear to face a significantly faster rate of long-term cognitive decline, and this risk is not explained by later rehospitalizations. Delirium prevention and monitoring may be critical components of preserving brain health after surgery.

Postoperative delirium is common in older adults and has been linked to dementia risk. This study suggests delirium itself—not simply the burden of later illness or rehospitalization—may be a key driver of accelerated cognitive decline, underscoring the importance of prevention and early recognition.

In a prospective cohort study published in JAMA Internal Medicine, investigators analyzed 560 community-dwelling adults aged 70 years or older who underwent major elective surgery and were followed for up to 5 years with repeated cognitive assessments. Participants completed a comprehensive battery of 11 neuropsychological tests before surgery and at 10 follow-up visits. Approximately 24% developed postoperative delirium.

Researchers found that rehospitalizations were associated with worsening cognition over time, with each rehospitalization linked to an additional decline of 0.19 General Cognitive Performance (GCP) units per year. However, postoperative delirium was associated with an even greater decline of 0.33 GCP units per year. Patients who experienced delirium were also more likely to be rehospitalized, with a 42% higher adjusted rate than those without delirium.

Contrary to expectations, accounting for rehospitalizations—including those involving intensive care or post-acute rehabilitation—had little effect on the association between delirium and cognitive decline. Statistical adjustment changed the delirium-cognition relationship by only 6% to 9%, suggesting rehospitalizations didn’t meaningfully mediate the long-term impact of delirium on cognition.

“We saw that delirium was associated with cognitive decline at a rate faster than what we would normally see with mild cognitive impairment and the effect was not mediated by rehospitalization,” said first author Tammy T. Hshieh, MD, MPH.

The findings reinforce postoperative delirium as one of the strongest predictors of long-term cognitive decline in older adults and highlight the need for strategies to prevent delirium and better understand its effects on brain health.

Source: Hshieh TT, et al. (2026, June 8). JAMA Intern Med. Rehospitalization and the Association of Postoperative Delirium With Cognitive Decline in Older Adults