A Frailty‐Based Plasma Proteomic Signature Capturing Overall Health and Well‐Being in Older Adults

Frailty is an age-related syndrome characterized by an increased vulnerability to adverse health outcomes in the face of stressors. By deriving a blood-based proteomic signature for frailty, the current study aimed to enhance the understanding of frailty biology and created a person-specific predictor for the risk of frailty and other adverse age-related health outcomes. A 25-protein signature (proteomic frailty index [pFI]) predictive of the cumulative frailty index (FI) in the LonGenity cohort was derived using a penalized regression method. The pFI was significantly correlated with the FI at baseline (Pearson r = 0.58) and showed significant associations with age-related chronic conditions, incident mortality, and clinical measures. In an independent cohort of 5195 participants in the Atherosclerosis Risk in Communities study, pFI was successfully validated with measured FI (r = 0.61, p < 0.001) and was associated with physical frailty at baseline (p < 0.001). The pFI was significantly associated with physical, clinical, and cognitive measures, as well as incident mortality (HR [95% CI] = 1.13 [1.12-1.14]) and dementia (HR [95% CI] = 1.07 [1.05-1.09]) after accounting for demographic factors. The pFI was further validated against FI (r = 0.45, p < 0.001) in a second independent study in 654 participants from the Baltimore Longitudinal Study of Aging. In conclusion, we identified and validated a 25-protein signature as an index of frailty that also captures overall well-being, health, and risk for key age-related diseases.