Serum cystatin C- versus creatinine-based definitions of acute kidney injury following cardiac surgery: A prospective cohort study

Aferdita Spahillari, Chirag R. Parikh, Kyaw Sint, Jay L. Koyner, Uptal D. Patel, Charles L. Edelstein, Cary S. Passik, Heather Thiessen-Philbrook, Madhav Swaminathan, Michael G. Shlipak

Research output: Contribution to journalArticle

Abstract

Background: The primary aim of this study was to compare the sensitivity and rapidity of acute kidney injury (AKI) detection by cystatin C level relative to creatinine level after cardiac surgery. Study Design: Prospective cohort study. Settings & Participants: 1,150 high-risk adult cardiac surgery patients in the TRIBE-AKI (Translational Research Investigating Biomarker Endpoints for Acute Kidney Injury) Consortium. Predictor: Changes in serum creatinine and cystatin C levels. Outcome: Postsurgical incidence of AKI. Measurements: Serum creatinine and cystatin C were measured at the preoperative visit and daily on postoperative days 1-5. To allow comparisons between changes in creatinine and cystatin C levels, AKI end points were defined by the relative increases in each marker from baseline (25%, 50%, and 100%) and the incidence of AKI was compared based on each marker. Secondary aims were to compare clinical outcomes among patients defined as having AKI by cystatin C and/or creatinine levels. Results: Overall, serum creatinine level detected more cases of AKI than cystatin C level: 35% developed a <25% increase in serum creatinine level, whereas only 23% had a <25% increase in cystatin C level (P < 0.001). Creatinine level also had higher proportions meeting the 50% (14% and 8%; P < 0.001) and 100% (4% and 2%; P = 0.005) thresholds for AKI diagnosis. Clinical outcomes generally were not statistically different for AKI cases detected by creatinine or cystatin C level. However, for each AKI threshold, patients with AKI confirmed by both markers had a significantly higher risk of the combined mortality/dialysis outcome compared with patients with AKI detected by creatinine level alone (P = 0.002). Limitations: There were few adverse clinical outcomes, limiting our ability to detect differences in outcomes between subgroups of patients based on their definitions of AKI. Conclusions: In this large multicenter study, we found that cystatin C level was less sensitive for AKI detection than creatinine level. However, confirmation by cystatin C level appeared to identify a subset of patients with AKI with a substantially higher risk of adverse outcomes.

Original languageEnglish (US)
Pages (from-to)922-929
Number of pages8
JournalAmerican Journal of Kidney Diseases
Volume60
Issue number6
DOIs
StatePublished - Dec 2012

Keywords

  • Perioperative
  • acute renal failure
  • creatinine
  • diagnosis

ASJC Scopus subject areas

  • Nephrology

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