Kidney function and markers of inflammation in elderly persons without chronic kidney disease: The health, aging, and body composition study

Inflammatory markers are elevated in persons with estimated glomerular filtration rates less than 60ml/min/1.73m(2). As cystatin C may detect small changes in kidney function not detected by estimated glomerular filtration rate, we evaluated the association between cystatin C and serum markers of inflammation in older adults with estimated glomerular filtration rate >= 60. This is an analysis using measures from the Health, Aging, and Body Composition Study, a cohort of well-functioning adults aged 70-79 years. Cystatin C correlated with all five inflammatory biomarkers: C-reactive protein ( r = 0.08), interleukin-6 ( r = 0.19), tumor necrosis factor alpha ( TNF-alpha) ( r = 0.41), soluble TNF receptor 1 ( STNF-R1) ( r = 0.61), and soluble TNF receptor 2 ( STNF-R2) ( r = 0.54); P < 0.0005 for all. In adjusted analyses, cystatin C concentrations appeared to have stronger associations with each biomarker compared with estimated glomerular filtration rate or serum creatinine. Participants with a cystatin C >= 1.0mg/l had significantly higher levels of all five biomarkers compared to those with a cystatin C < 1.0 ( mean differences ranging 16-29%, all P < 0.05). Cystatin C has a linear association with inflammatory biomarkers in an ambulatory elderly cohort with estimated glomerular filtration rates >= 60; associations are particularly strong with TNF-alpha and the STNF-R.