Raised serum cystatin C can be a potential biomarker of frailty detected by cumulative deficit model

OBJECTIVE: Identification of frailty by clinical criteria is often delayed to the advanced stage. A reliable biomarker to identify frailty or its risk does not currently exist. We aimed to determine the association between serum cystatin C and frailty in subjects without renal dysfunction. METHODS: We carried out a cross‐sectional observational study in the Department of Geriatric Medicine, All India Institute of Medical Sciences, New Delhi, India. The study involved 125 participants, aged 65 years or older. Frailty status was assessed with Frailty Index criteria (cumulative deficit model). Serum cystatin C was estimated with the nephelometry method and its association with frailty was analyzed. RESULTS: Mean age of the study sample was 76.32 years with 72 (57.6%) male and 53 (42.4%) female participants. Seventy‐three subjects were frail; the mean cystatin C levels in the frail and non‐frail groups were 1.28 mg/L (±0.39) and 1.12 mg/L (±0.27), respectively, and the difference was significant (P < 0.05). A cutoff of 1.12 mg/L was found to be 60.27% sensitive and 57.69% specific in identification of frailty. Multivariate analysis showed that higher cystatin C level was associated with 2.52 (1.05‐6.02) times the risk of being frail. CONCLUSION: Higher levels of cystatin C were found in frail subjects. Cystatin C seems to be a promising marker for identifying frailty in older adults without renal abnormalities.