Cystatin C and Cardiovascular Risk in the General Population

Introduction and objectives. Cystatin C has been proposed as a novel marker of renal function and as a predictor of cardiovascular risk in the elderly. The aim of this study was to determine the prevalence of an elevated cystatin C level in the general population and its relationship with cardiovascular risk factors and disease. Methods. This descriptive epidemiologic cross-sectional study involved a simple randomized sample of individuals aged >49 years from the general population, and was based on personal health records. From the final selection of 415 individuals, 359 underwent cystatin C measurement using a immunonephelometric assay. The cut-point used was that recommended for the method in adults. Results. Of the 359 individuals (mean standard deviation age, 64 +/- 10 years, 63.5% female) studied, 17.3% (95% confidence interval [CI] 13.4%-21.2%) had an elevated cystatin C level. The mean level was 0.81 +/- 0.21 mg/L, and increased with age. Elevation of the cystatin C level was associated with: older age (P<.0001); high measures of systolic blood pressure (P<.0001), hemoglobin A(1c) (P=.031), triglycerides (P=.019), homocysteine (P<.0001), C-reactive protein (P=.015), fibrinogen (P=.006) and microalbuminuria (P=.001); and a low high-density lipoprotein cholesterol level (P=.021) and estimated glomerular filtration rate (P<.0001). Associated cardiovascular diseases included coronary heart disease (P=.013) and heart failure (P=.038). The main factors independently associated with an elevated cystatin C level were diabetes (odds ratio [OR]=5.37), male sex (OR=4.91) and decreased glomerular filtration (OR=0.83). Conclusions. The prevalence of an elevated cystatin C level in the general population was found to be high and was associated with the presence of classical cardiovascular risk factors such as diabetes, hypertension and chronic renal disease, along with higher levels of C-reactive protein, homocysteine and fibrinogen.