Characterization of the plasma proteomic profile of frailty phenotype.

Frailty is a risk factor for poor health outcomes in older adults. The aim of this study was to identify plasma proteomic biomarkers of frailty in 752 men and women older than 65 years of age from the InCHIANTI study. One thousand three hundred one plasma proteins were measured using an aptamer-based assay. Associations of each protein with frailty status were assessed using logistic regression and four proteins creatine kinase M-type (CKM), B-type (CKB), C-X-C motif chemokine ligand 13 (CXCL13), and thrombospondin 2 (THBS2) were associated with frailty status. Two proteins, cyclin-dependent kinase 5 (CDK5/CDK5R1) and interleukin 1 alpha (IL1A), were associated with worsening of frailty status over time in volunteers free of frailty at baseline. Using partial least squares discriminant analysis (PLS-DA), data of 1301 proteins was able to discriminate between frail and non-frail with a 2% error rate. The proteins with greater discriminatory ability represented the inflammation, blood coagulation, and cell growth pathways. The utility of these proteins as biomarkers of frailty should be further explored.