Neurofilament Light in Serum and Cerebrospinal Fluid of Hip Fracture Patients with Delirium.

Background: Delirium is associated with new-onset dementia, suggesting that delirium pathophysiology involves neuronal injury. Neurofilament light (NFL) is a sensitive biomarker for neuroaxonal injury.

Methods: NFL was measured in cerebrospinal fluid (CSF) (n = 130), preoperative serum (n = 192), and postoperative serum (n = 280) in hip fracture patients, and in CSF (n = 123) and preoperative serum (n = 134) in cognitively normal older adults undergoing elective surgery. Delirium was diagnosed with the Confusion Assessment Method.

Results: Median serum NFL (pg/mL) was elevated in delirium in hip fracture patients (94 vs. 54 pre- and 135 vs. 92 postoperatively, both p < 0.001). Median CSF NFL tended to be higher in hip fracture patients with delirium (1,804 vs. 1,636, p = 0.074). Serum and CSF NFL were positively correlated (ρ = 0.56, p < 0.001).

Conclusion: Our findings support an association between neuroaxonal injury and delirium. The correlation between serum and CSF NFL supports the use of NFL as a blood biomarker in future delirium studies.