title: Association of Peak Changes in Plasma Cystatin C and Creatinine With Death After Cardiac Operations.
abstract: BACKGROUND
  Acute kidney injury is a risk factor for death in cardiac surgical patients. Plasma cystatin C and creatinine have different temporal profiles in the postoperative setting, but the associations of simultaneous changes in both filtration markers compared with change in only one marker with prognosis after hospital discharge are not well described.
  
  
  METHODS
  This is a longitudinal study of 1,199 high-risk adult cardiac surgical patients in the TRIBE-AKI (Translational Research Investigating Biomarker Endpoints for Acute Kidney Injury) Consortium who survived hospitalization. We examined in-hospital peak changes of cystatin C and creatinine in the 3 days after cardiac operations. We evaluated associations of these filtration markers with death, adjusting for demographics, operative characteristics, medical comorbidities, preoperative estimated glomerular filtration rate, preoperative urinary albumin-to-creatinine ratio, and site.
  
  
  RESULTS
  During the first 3 days of hospitalization, nearly twice as many patients had a 25% or higher rise in creatinine (30%) compared with a 25% or higher peak rise in cystatin C (15%). The risk of death was higher in those with elevations in cystatin C (adjusted hazard ratio [HR], 1.83; 95% confidence interval [CI], 1.4 to 2.37) or creatinine (adjusted HR, 1.90; 95% CI, 1.32 to 2.72) compared with patients who experienced a postoperative decrease in either filtration marker. Patients who had simultaneous elevations of 25% or higher in cystatin C and creatinine were at similar adjusted risk for 3-year mortality (HR, 1.79; 95% CI, 1.03 to 3.1) as those with a 25% or higher increase in cystatin C alone (HR, 2.2; 95% CI, 1.09 to 4.47).
  
  
  CONCLUSIONS
  Elevations in creatinine postoperatively are more common than elevations in cystatin C. However, elevations in cystatin C appeared to be associated with a higher risk of death after hospital discharge.
authors.affiliation: Division of Nephrology, University of California, San Francisco, San Francisco, California. Electronic address: meyeon.park@ucsf.edu.
authors.forename: Meyeon
authors.initials: M
authors.lastname: Park
authors.affiliation: Division of General Internal Medicine, San Francisco VA Medical Center, University of California, San Francisco, San Francisco, California.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Shlipak
authors.affiliation: Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada.
authors.forename: Heather
authors.initials: H
authors.lastname: Thiessen-Philbrook
authors.affiliation: Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada; Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.
authors.forename: Amit X
authors.initials: AX
authors.lastname: Garg
authors.affiliation: Section of Nephrology, Department of Medicine, University of Chicago, Chicago, Illinois.
authors.forename: Jay L
authors.initials: JL
authors.lastname: Koyner
authors.affiliation: Division of Nephrology, Mount Sinai School of Medicine, New York, New York.
authors.forename: Steven G
authors.initials: SG
authors.lastname: Coca
authors.affiliation: Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Chirag R
authors.initials: CR
authors.lastname: Parikh
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000209:etiology / Q000401:mortality; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000401:mortality*; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D005260:Female; D006760:Hospitalization; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D013997:Time Factors
chemical_list: D015415:Biomarkers; D055316:Cystatin C; D003404:Creatinine