Correlation between serum biomarkers and degree of physical frailty in older adults: a cross-sectional study in a hospital in Lima, Peru

Objective: To determine the correlation between the degree of frailty and serum biomarkers in older adults attending a hospital in Lima, Peru. Materials and methods: An observational, analytical, cross-sectional study was conducted in 66 adults aged ≥ 65 years treated at Hospital Central de la Fuerza Aérea del Perú (Central Hospital of the Peruvian Air Force) between 2024 and 2025. Frailty was assessed using the Short Physical Performance Battery (SPPB). Serum biomarkers analyzed included interleukin-6 (IL-6), C-reactive protein (CRP), D-dimer, vitamin D, fibrinogen, hemoglobin, basal insulin, glucose, ferritin, albumin, and vitamin B12. Fasting blood samples were collected using standardized procedures. Consecutive non-probability sampling was employed. Patients with moderate-to-severe dementia, severe mobility impairment, active cancer, or renal disease requiring hemodialysis were excluded. Results: The mean age was 79.87 ± 9.15 years, and the mean SPPB score was 8.79 ± 2.4. Significant positive correlations were found between SPPB score and hemoglobin (r = 0.48; p < 0.01), ferritin (r = 0.25; p = 0.03), and serum albumin (r = 0.50; p < 0.01). Negative correlations were observed with IL-6 (r =-0.27; p = 0.02), CRP (r =-0.33; p < 0.01), fibrinogen (r =-0.24; p = 0.04), and D-dimer (r =-0.23; p = 0.05). In a multivariate analysis adjusted for clinical covariates (sex; the Barthel Index for Activities of Daily Living; and the Strength, Ambulation, Rising from a Chair, Stair Climbing, and History of Falling [SARC-F] score), D-dimer (β =-0.22; 95% CI:-0.39 to-0.05; p = 0.01) and fibrinogen (β =-0.45; 95% CI:-0.78 to-0.12; p < 0.01) remained significantly and negatively associated with physical performance, while traditional inflammatory markers showed no independent associations. Conclusions: Coagulation markers, particularly D-dimer and fibrinogen, emerge as independent biomarkers of frailty in Peruvian older adults. Hemostatic disorders appear to be a more specific biological correlate of physical frailty than general systemic inflammation, suggesting their potential utility as accessible tools for early identification of frailty in a comprehensive geriatric assessment.