Observational Study Examining the Association of Baseline Frailty and Postcardiac Surgery Delirium and Cognitive Change

Abstract

BACKGROUND: Frailty is a geriatric syndrome thought to identify the most vulnerable older adults, and morbidity and mortality has been reported to be higher for frail patients after cardiac surgery compared to nonfrail patients. However, the cognitive consequences of frailty after cardiac surgery have not been well described. In this study, we examined the hypothesis that baseline frailty would be associated with postoperative delirium and cognitive change at 1 and 12 months after cardiac surgery. METHODS: This study was nested in 2 trials, each of which was conducted by the same research team with identical measurement of exposures and outcomes. Before surgery, patients were assessed with the validated “Fried” frailty scale, which evaluates 5 domains (shrinking, weakness, exhaustion, low physical activity, and slowed walking speed) and classifies patients as nonfrail, prefrail, and frail. The primary outcome was postoperative delirium during hospitalization, which was assessed using the Confusion Assessment Method, Confusion Assessment Method for the Intensive Care Unit, and validated chart review. Neuropsychological testing was a secondary outcome and was generally performed within 2 weeks of surgery and then 4–6 weeks and 1 year after surgery, and the outcome of interest was change in composite Z-score of the test battery. Associations were analyzed using logistic and linear regression models, with adjustment for variables considered a priori (age, gender, race, education, and logistic European System for Cardiac Operative Risk Evaluation). Multiple imputation was used to account for missing data at the 12-month follow-up. RESULTS: Data were available from 133 patients with baseline frailty assessments. Compared to nonfrail patients (13% delirium incidence), the incidence of delirium was higher in prefrail (48% delirium incidence; risk difference, 35%; 95% CI, 10%–51%) and frail patients (48% delirium incidence; risk difference, 35%; 95% CI, 7%–53%). In both univariable and multivariable models, the odds of delirium were significantly higher for prefrail (adjusted odds ratio, 6.43; 95% CI, 1.31–31.64; P = .02) and frail patients (adjusted odds ratio, 6.31; 95% CI, 1.18–33.74; P = .03) compared to nonfrail patients. The adjusted decline in composite cognitive Z-score was greater from baseline to 1 month only in frail patients compared to nonfrail patients. By 1 year after surgery, there were no differences in the association of baseline frailty with change in cognition. CONCLUSIONS: Compared to nonfrail patients, both prefrail and frail patients were at higher risk for the primary outcome of delirium after cardiac surgery. Frail patients were also at higher risk for the secondary outcome of greater decline in cognition from baseline to 1 month, but not baseline to 1 year, after surgery.

Enhanced Recovery After Cardiac Surgery (ERAS Cardiac) Recommendations: An Important First Step—But There Is Much Work to Be Done

“…with long-term cognitive changes. [49][50][51] Preliminary data even have suggested that the presence of delirium is more important than the severity of illness in predicting intensive care unit length of stay. 52 Delirium in the postoperative phase of cardiac surgical care occurs in all ages, affecting between 20% and 80% of patients.…”

Frailty and delirium in hospitalized older adults: A systematic review with meta-analysis

“… 335 Prospective cohort study 76.8±8.1 CFS ‡‡‡ (Frail>5/7) CAM † Prevalence of frailty HR ‡ 0.21 (0.17 - 0.26) Prevalence of delirium HR ‡ 0.12 (0.09 - 0.16) Risk of delirium in frail patients RR § 3.79 (2.16 - 6.63) Alabaf Sabbaghi, et al, 2018 31 United Kingdom Emergency Sector To compare the clinical characteristics, frailty, dementia and delirium in a hospital with a specialized counseling team for frail older adults versus usual treatment. 6,191 Retrospective and documentary 84.6±6.3 CFS ‡‡‡ 4-ATM §§§ Prevalence of frailty HR ‡ 0.05 (0.04 - 0.06) Prevalence of delirium HR ‡ 0.12 (0.11 - 0.13) Nomura, et al, 2018 32 Japan Cardiac surgery To examine the hypothesis that baseline frailty would be associated with postoperative delirium and to cognitive changes from 1 to 12 months after a cardiac surgery. 133 Prospective cohort study Robust 69.3±7.9 Frail 73.4±8.09 Fried’s Phenotype CAM † and CAM-ICU |||||| Prevalence of frailty HR ‡ 0.34 (0.26 - 0.42) Prevalence of delirium HR ‡ 0.48 (0.40 - 0.56) Risk of delirium in frail patients RR § 1.04 (0.68 - 1.58) Goudzwaard, et al, 2018 33 Netherlands Cardiac surgery (TAVI ‡‡ ) To investigate the association between a new Erasmus Frailty Score and short- and long-term results after TAVI ‡‡ .…”

“…The scarcity of studies evaluating frailty as a predisposing factor to delirium 10 , 21 , 37 - 38 , 41 was an unexpected finding of this paper, as the association between these conditions is accepted in the clinical practice. No relationship was observed between frailty and development of delirium in seven of the 26 studies analyzed, (RR: 1; 95% CI: 0.51-1.98) 25 , (RR: 0.90; 95% CI: 0.36-2.23) 21 , (RR: 0.48; 95% CI: 0.26-0.87) 29 , (RR: 1.04; 95% CI: 0.68-1.54) 32 , (RR: 1.14; 95% CI: 0.85-1.53) 23 , (RR: 0.90; 95% CI: 0.84-0.98) 27 , (RR: 0.27; 95% CI: 0.17-0.43) 24 .…”

Frailty Syndrome in Older Adults with Cardiovascular Diseases–What Do We Know and What Requires Further Research?

“…A meta-analysis showed that FS and pre-frailty were associated with greater adjusted operative mortality and adjusted perioperative complications, and FS was associated with almost 5-fold risk of non-home discharge [ 49 ]. Preoperative FS also predicts prolonged respiratory therapy, prolonged stay in the intensive care unit, functional decline, postoperative delirium, reoperations, readmission rate, increased risk of institutional discharge, and early, mid-term, and late mortality [ 50 , 52 , 80 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ].…”