CST3 and acute kidney injury: The purpose of our study was to analyze whether cystatin C and eGFR formulas based on cystatin C (eGFRcyst) identify a subgroup of patients with an increased risk of progression of renal failure, cardiovascular events, and overall mortality among a group of selected patients, improving the standard method of creatinine (eGFRcreat) for the diagnosis and followup of renal failure.