Advanced Glycation End Products for Preoperative Frailty Screening in Elderly Cardiac Surgery Patients

Background: Advanced glycation end products (AGEs) are a potential biomarker of biological age. Skin Auto Fluorescence (SAF) can assess AGEs non-invasively. We evaluated the association of SAF levels with frailty and its predictive ability for adverse outcomes in elderly cardiac surgery patients. Methods & Results: We measured SAF level in cardiac surgery patients aged ≥70 and analyzed the correlation with frailty diagnosed with geriatric assessment. A decision algorithm for frailty screening was developed using Conditional Interference Tree analysis and compared with the Frailty Phenotype (FP), a validated frailty assessment tool. We evaluated the association of SAF level with severe postoperative complications and a composite endpoint of one-year disability (defined by WHO Disability Assessment Schedule 2.0 (WHODAS 2.0) questionnaire) and mortality with Poisson regression analyses. Among 555 enrolled patients, 122 (22%) were classified as frail. Of all frailty characteristics, SAF level was most strongly associated with dependent living status (aRR 2.61 (95% CI 1.23-5.53) and handgrip strength (aRR 1.72 (95% CI 1.28-2.32). A decision algorithm including SAF level, sex, prescription drugs, preoperative hemoglobin and EuroSCORE II resulted in a C-statistic of 0.72 (95% CI 0.67-0.77) vs 0.66 (95% CI 0.61-0.71) for the FP. SAF level was also associated with disability/death after one year (aRR 1.18 (95% CI 1.06-1.30). The RR for severe complications was 1.32 (95% CI 0.99-1.75). Conclusion: Higher SAF level is associated with frailty in elderly cardiac surgery patients, as well as an increased risk of death and disability. This biomarker could potentially optimize preoperative screening for cardiac surgery.