News

Impaired Cognition in Elderly Impacts Postoperative Outcomes

View on the News

Global Evaluation Makes a Difference

This study further corroborates what we already know, in that patients with baseline cognitive dysfunction are at significant risk of delirium when hospitalized, with increased morbidity and mortality that can extend several months beyond the hospital stay. Because persons over age 65 comprise the fastest-growing population, this is going to be an increasing issue as time goes on.

Dr. Stacie Levine

This also highlights the importance of a global assessment when conducting preoperative assessments on older adults. We are skilled at medical clearance with regards to cardiac status, but also need to consider the brain as being another “at-risk” organ. The identification of persons with underlying cognitive dysfunction should lead to thoughtful decisions regarding perioperiative risk-reduction, such as route/type of anesthesia, type of surgical procedure, and delirium prevention strategies. By doing a risk-benefit calculation we can consider the best route of care for each patient, including whether they are a good candidate for surgery at all. In summary, preoperative assessment of older adults requires a global evaluation that includes not only cardiac risk assessment, but also standardized cognitive and functional assessments.

The next question is how to effectively risk-stratify and make clinical decisions based on patients’ level of cognitive dysfunction. For example, at what level of cognitive impairment do we decide a person is not a good candidate for surgery? Or, which surgical patients should be placed on more resource-intensive delirium risk prevention protocols? As a geriatrician, I identify and attempt to modify all potential factors that can put any older adult at risk for delirium such as sensory impairment, dehydration, and certain medications. Dr. Sharon Inouye’s Hospital Elder Life Program (HELP) is an example of a successful program in reducing incidence of delirium by proactively using preventative strategies. Ideally every hospital should have some version of this model in place for all older adults, but at the very least targeting medical and surgical patients deemed to be at highest risk.

STACIE LEVINE, M.D., is an associate professor of medicine in the section of geriatrics and palliative medicine at University of Chicago. She was core faculty in the development and implementation of the Curriculum for the Hospitalized Aging Medical Patient.


 

Impaired cognition among older adults who undergo elective surgery is significantly associated with adverse postoperative outcomes, including increased complications, length of stay, and long-term mortality, results from a single-center study showed.

In addition, delirium was found to be an effect modifier in the relationship between impaired cognition and adverse postoperative outcomes.

"The most striking finding is that delirium appears to work as part of a causal pathway between baseline impaired cognition and long-term mortality," lead investigator Dr. Thomas N. Robinson said in an interview before the annual meeting of the Western Surgical Association, where the work was presented.

In what he said is the first study of its kind, Dr. Robinson, of the department of surgery at the University of Colorado, Denver, and his associates prospectively evaluated 186 adults aged 65 and older who underwent an elective operation requiring postoperative ICU admission.

To assess preoperative baseline cognitive function, they used the validated Mini-Cog test, which combines an uncued three-item recall test with a clock drawing task. Impaired cognition was defined as a Mini-Cog score of 3 or less.

To assess delirium, the researchers used the Confusion Assessment Method for the ICU, a validated tool that evaluates delirium based on fluctuation in mental status, inattention, disorganized thinking, and altered level of consciousness.

"Delirium appears to work as part of a causal pathway between baseline impaired cognition and long-term mortality."

To determine adverse outcomes, they used definitions from the Veterans Affairs Surgical Quality Improvement Program.

Dr. Robinson, who also holds an appointment in the department of surgery at the Denver Veterans Affairs Medical Center, reported that the mean age of the 186 patients was 73 years and 96% were male. Nearly half (44%) had impaired cognition.

Compared with their counterparts who had normal cognition at baseline, those with impaired cognition had a higher rate of one or more complications (41% vs. 24%, respectively), a higher incidence of delirium (78% vs. 37%), longer hospital stays (a mean of 15 vs. 9 days), a higher rate of discharge to an institutional care facility (42% vs. 18%), a higher 30-day readmission rate (21% vs. 10%), and a higher 6-month mortality (11% vs. 5%). All differences were statistically significant.

Dr. Robinson also reported that the hazard ratio for death was 2.77 higher among patients with impaired cognition and delirium at baseline compared with patients with normal cognition and delirium. On the other hand, the hazard ratio for death was 1.86 times higher among patients who had impaired cognitive function but no delirium at baseline.

In their abstract, the researchers noted certain limitations of the study, including the fact that nearly all patients were male and that a wide variety of operations were included, which "leads to large variability in measurements such as blood loss, operating room time, and length of stay."

They went on to conclude that "recognition of the brain’s function as a relevant marker of postoperative events has implications on the clinician’s ability to counsel their older patients about the anticipated postoperative course. In the future, preoperative risk stratification will likely not be based on physiologic compromise of a single organ system alone. Instead, the sum of compromise across multiple health-related domains (e.g., cognition, function, nutrition, disease burden) will likely be used to forecast postoperative outcomes."

The study received financial support from the National Institute on Aging and the American Geriatrics Society. Dr. Robinson said that he had no relevant financial disclosures.

Recommended Reading

Three Factors Increase Risk for Hip Replacement Revision
MDedge Surgery