BACKGROUND

Advanced glycation end products (AGEs) are potential biomarkers 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 older cardiac surgery patients.

METHODS

This was a retrospective analysis of prospectively acquired data from a two-center observational cohort study. We measured SAF level in cardiac surgery patients aged ≥70. Primary outcome was preoperative frailty. A comprehensive frailty assessment was performed before surgery based on 11 individual tests assessing the physical, mental, and social domain. Frailty was defined as at least 1 positive test in each domain. Secondary outcome measures were severe postoperative complications and a composite endpoint of 1-year disability (defined by WHO Disability Assessment Schedule 2.0 (WHODAS 2.0) questionnaire) or mortality.

RESULTS

Among 555 enrolled patients, 122 (22%) were frail. SAF level was most strongly associated with dependent living status (aRR 2.45 (95% CI 1.28-4.66)) and impaired cognition (aRR 1.61 (95% CI 1.10-2.34)). A decision algorithm to identify frail patients 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). SAF level was also associated with disability or death after 1 year (aRR 1.38 (95% CI 1.06-1.80)). The aRR for severe complications was 1.28 (95% CI 0.87-1.88).

CONCLUSIONS

Higher SAF level is associated with frailty in older cardiac surgery patients, as well as an increased risk of death or disability. This biomarker could potentially optimize preoperative risk stratification for cardiac surgery.