Six-Year Cognitive Trajectory in Older Adults Following Major Surgery and Delirium

Abstract

ImportanceThe study results suggest that delirium is the most common postoperative complication in older adults and is associated with poor outcomes, including long-term cognitive decline and incident dementia.ObjectiveTo examine the patterns and pace of cognitive decline up to 72 months (6 years) in a cohort of older adults following delirium.Design, Setting, and ParticipantsThis was a prospective, observational cohort study with long-term follow-up including 560 community-dwelling older adults (older than 70 years) in the ongoing Successful Aging after Elective Surgery study that began in 2010. The data were analyzed from 2021 to 2022.ExposureDevelopment of incident delirium following major elective surgery.Main Outcomes and MeasuresDelirium was assessed daily during hospitalization using the Confusion Assessment Method, which was supplemented with medical record review. Cognitive performance using a comprehensive battery of neuropsychological tests was assessed preoperatively and across multiple points postoperatively to 72 months of follow-up. We evaluated longitudinal cognitive change using a composite measure of neuropsychological performance called the general cognitive performance (GCP), which is scaled so that 10 points on the GCP is equivalent to 1 population SD. Retest effects were adjusted using cognitive test results in a nonsurgical comparison group.ResultsThe 560 participants (326 women [58%]; mean [SD] age, 76.7 [5.2] years) provided a total of 2637 person-years of follow-up. One hundred thirty-four participants (24%) developed postoperative delirium. Cognitive change following surgery was complex: we found evidence for differences in acute, post–short-term, intermediate, and longer-term change from the time of surgery that were associated with the development of postoperative delirium. Long-term cognitive change, which was adjusted for practice and recovery effects, occurred at a pace of about −1.0 GCP units (95% CI, −1.1 to −0.9) per year (about 0.10 population SD units per year). Participants with delirium showed significantly faster long-term cognitive change with an additional −0.4 GCP units (95% CI, −0.1 to −0.7) or −1.4 units per year (about 0.14 population SD units per year).Conclusions and RelevanceThis cohort study found that delirium was associated with a 40% acceleration in the slope of cognitive decline out to 72 months following elective surgery. Because this is an observational study, we cannot be sure whether delirium directly causes subsequent cognitive decline, or whether patients with preclinical brain disease are more likely to develop delirium. Future research is needed to understand the causal pathway between delirium and cognitive decline.

Risk factors for dementia in older intensive care unit (ICU) survivors

“…The primary outcome of this study was an initial diagnosis of post‐ICU dementia within 5 years after ICU hospitalization. This timeline was longer than previous ICU survivor studies which examined cognition for about 1 year after ICU hospitalization, because other cohort studies examining delirium in non‐ICU settings, most notably the Successful Aging after Elective Surgery study, showed cognitive decline as long as 6 years after hospitalization 28 . Initial diagnosis of post‐ICU dementia was defined as the initial coding in the EMR of any of the International Classification of Diseases (ICD)‐9 and ‐10 codes for AD dementia and other related dementias (Table S1A in supporting information) or being prescribed medications for dementia (Table S1B).…”

Structural disconnectivity in postoperative delirium: A perioperative two‐center cohort study in older patients

“…Together with the loss of gray matter volume after episodes of POD, 36 our findings could represent the structural correlate of worsening cognitive trajectories in POD patients. 37 Future studies need to investigate whether this white and gray matter depletion after episodes of delirium may lead to cognitive decline and eventually the development of dementia.…”

Successful aging after elective surgery II: Study cohort description

“…Delirium's adverse impact is profound including functional decline, accelerated cognitive decline, prolonged hospitalization, and higher healthcare costs (approximately $32.9 billion nationally per year) 5,6 . The development of delirium serves as a marker of brain vulnerability, and postoperative delirium has been associated with 40% accelerated cognitive decline 72 months following surgery 6,7 . However, the pathophysiological pathways linking delirium to dementia remain unclear 8 …”

“…5,6 The development of delirium serves as a marker of brain vulnerability, and postoperative delirium has been associated with 40% accelerated cognitive decline 72 months following surgery. 6,7 However, the pathophysiological pathways linking delirium to dementia remain unclear. 8 We previously conducted the Successful Aging after Elective Surgery (SAGES I) Study following a cohort of over 560 older adults undergoing surgery.…”