Frailty, age, cognition impact odds for post-intensive care syndrome in ICU survivors

Key takeaways:

• Survivors with a recovery trajectory consistent with post-intensive care syndrome had poorer cognitive function at baseline and over 12 months.
• This group also had more impairment in performing daily activities.

SAN FRANCISCO — Greater frailty, older age and worse cognition heightened the odds for a post-intensive care syndrome recovery trajectory in ICU survivors, according to data shared at the American Thoracic Society International Conference.

“In particular, greater baseline frailty was strongly associated with development of post-intensive care syndrome (PICS) which suggests that pre-illness frailty is an important predictor of functional trajectories following critical illness,” Justin Banerdt, MD, MPH, pulmonary and critical care fellow in the division of allergy, pulmonary and critical care medicine at Vanderbilt University Medical Center, told Healio.

In this retrospective analysis, Banerdt and colleagues evaluated 804 adults who survived the ICU for respiratory failure and/or shock from two study cohorts (BRAIN-ICU and MIND-ICU) to identify and illustrate recovery trajectories of critical illness survivors.

Researchers used three assessments — Mini Mental State Exam (MMSE T-score), Katz Index of Independence in Activities of Daily Living (Katz ADL) and Functional Activities Questionnaire (FAQ) — taken by patients at baseline, 3 months and 12 months to chart trajectories.

Using multivariate joint latent class modeling and joint survival analysis, two patient classes with differing recovery trajectories emerged. The study showed that many of the patients belonged to class one, which included 620 patients (median age, 61.5 years). The remaining 184 patients (median age, 66 years) belonged to class two, which was described as being “consistent with post-intensive care syndrome” in the abstract.

Between the two classes, researchers found that the MMSE T-score over the 12 months studied was always poorer among those in class two vs. class one, and the predicted degree of change from baseline was smaller in class two, indicating less recovery of cognitive function.

When interpreting results from the Katz ADL assessment, Banerdt noted that in the version they used, a higher score indicated greater dependence (disability). The Katz ADL score at baseline was lower for patients in class one vs. two and did not change over the course of 12 months in the class one group. In contrast, this score went up between baseline and 12 months among patients in class two.

For the FAQ, Banerdt said a higher score on a scale of 0 to 30 signals greater dependency/impairment. Researchers found a higher FAQ score in class two vs. one at baseline and over the course of 12 months. Between baseline and 12 months, class two also had a larger increase in this score.

“I was surprised that patients with the PICS trajectory had more dependence on ADLs and instrumental ADLs (IADLs) which progressively worsened through 12-month follow up,” Banerdt told Healio. “It is striking that not only did this group of patients with PICS show no evidence of recovery in performing ADLs and IADLs, but their functional deficits in these areas actually continued to worsen even up to a year after their critical illness.

“These findings give us a better understanding of how different domains of function change over time for patients with PICS, which may help clinicians develop more targeted interventions to improve patient recovery trajectories such as cognitive, physical and occupational therapy,” he added.

Survival was also lower for patients in class two. The 12-month survival probability in class one was 78%, whereas this probability was 51.3% in class two, according to the study.

In a logistic regression model, researchers observed three characteristics that significantly raised a patient’s likelihood for belonging to class two: greater frailty at ICU admission (OR = 4.56; P < .01), older age (OR = 1.35; P = .02) and worse baseline cognition (OR = 1.19; P < .01).

“Knowing that older age, worse baseline cognition and worse baseline frailty were associated with the PICS trajectory may help clinicians identify patients who are at an increased risk of developing PICS so they can receive appropriate care and support as they recover from their critical illness,” Banerdt told Healio. “This could lead to the development of a validated clinical prediction tool for more rigorously assessing which patients may develop PICS that could then be implemented more widely in a variety of clinical settings.”

This study did not find a significant link between class two likelihood and mean illness severity or between class two likelihood and delirium duration, which Banerdt told Healio was surprising but “further emphasizes the importance of baseline frailty and baseline cognitive function as risk factors for PICS.”

Moving forward, Banerdt said there are several areas his team would like to explore related to this topic.

“We are interested in developing and validating a clinical prediction tool for PICS, studying possible pathophysiologic mechanisms underlying PICS including mitochondrial dysfunction and assessing whether targeted interventions can improve recovery trajectories for these patients,” Banerdt told Healio.

“I am also interested in expanding our research to resource-limited settings in low- and middle-income countries,” he added.

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For more information:

Justin Banerdt, MD, MPH, can be reached at justin.k.banerdt.1@vumc.org.