In another study called the Cardiovascular Health Study, which involved over 4000 patients who were elderly without chronic kidney disease (CKD), eGFR (estimated glomerular filtration rate) was measured using the MDRD equation and cystatin C. The study found strong associations between cystatin C concentrations and several adverse outcomes, including death (hazard ratio (HR 1.33), incident heart failure (HR 1.28), stroke (HR 1.22), and myocardial infarction (HR 1.20). This evidence concerns the gene CST3 and chronic kidney disease.