Association of cystatin C with 20-year mortality risk in the general US population: a cohort study

Impaired kidney function is associated with increased mortality. This study evaluated the association between serum cystatin C levels and long-term all-cause, cardiovascular, and cerebrovascular mortality in the general U.S. population. Impaired kidney function is associated with increased mortality. This study evaluated the association between serum cystatin C levels and long-term all-cause, cardiovascular, and cerebrovascular mortality in the general U.S. population. During a median follow-up of 207 months (interquartile range [IQR]: 188.0–227.0), 3,538 participants died. The median baseline age was 44.0 years (IQR: 33.0–57.0). Participants were categorized into quintiles based on serum cystatin C, creatinine, and estimated glomerular filtration rate (eGFR). Multivariate analysis, revealed a significant association of cystatin C’s third, fourth, and fifth quintiles with an increased risk of all-cause mortality. Compared to the first quintile, the hazard ratios (HR) [95% confidence intervals (CI)] for all-cause mortality were as follows: second quintile, 1.05 (0.82–1.34); third quintile, 1.29 (1.03–1.60); fourth quintile, 1.46 (1.17–1.83); and fifth quintile, 2.32 (1.86–2.89). Furthermore, the second quintile had a 1.78-fold risk (HR: 1.78, 95%CI: 1.11–2.86), the fourth quintile had a 1.85-fold risk (HR: 1.85, 95% CI: 1.17–2.92), and the fifth quintile had a 2.97-fold risk of cardiovascular mortality (HR: 2.97, 95% CI: 1.89–4.68). However, adjusted analysis did not reveal creatinine and eGFR as predictors for any outcome. After adjusting for confounding factors, creatinine and eGFR were not significantly associated with the risk of death. Cystatin C emerged as an independent predictor of all-cause and cardiovascular mortality with in the general population of the US.