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Background and Aims Surgical and anesthetic trauma cause impaired frailty and cognitive dysfunction, especially in elderly patients. Recently, frailty has been linked to cognitive impairment on similar pathophysiological mechanisms (1,2). We aimed to investigate if such an association could be established between plasma Aß and cerebrospinal fluid Nf proteins and clinical scores.

Methods After Institutional Review Board approval (KA 21/124), consecutive patients > 65 years, with informed consent, scheduled for lower extremity orthopedics surgery were enrolled. A sample size of 127 was calculated with a power of 80% at the ‰8.3 significance level Prior to surgery, patients were interviewed for validated Fried Frailty Index (Turkish version) (3) and Mini Mental State Examination (MMSE). Additionally, the venous blood sampling was performed for plasma neuron-specific enolase (NSE), and amyloid β protein 40-42 (Aß1–40/42). On the day of surgery, we collected lumbar CSF during spinal anesthesia for analysis of neurofilament light/heavy chain (Nf-L/H) and brain-derived neurotrophic factor (BDNF). MMSE and frailty were evaluated at postoperative 4th week.

Results 129 patients comprised the study. Older age was associated with significant increase in preoperative frailty and significant decrease in preoperative MMSE scores (p=0.009, p=0.005). Postoperative frailty and MMSE scores were higher in comparison to preoperative ones (p<0.001). No association was detected between plasma, CSF biochemicals and clinical scores.

Conclusions Frailty and cognitive impairment are reported to have common inflammatory markers, proteins, and genetics (4). However, the studied Aß and neurofilament chain proteins aren’t among them. Further research should explore this relationship.