title: The discrepancy between serum creatinine and cystatin C can predict renal function after treatment for postrenal acute kidney injury: multicenter study and pooled data analysis.
abstract: BACKGROUND
  Although serum cystatin C and creatinine are used as practical markers of renal function, the discrepancy between them in postrenal acute kidney injury (AKI) cases was reported. The aim of this study was to determine whether the preoperative serum cystatin C (pre-CysC) level could predict clinical outcomes after treatment in patients with postrenal AKI.
  
  
  METHODS
  Patients who underwent urological interventions with postrenal AKI were enrolled in this prospective observational study. Associations among preoperative serum creatinine (pre-sCr), pre-CysC, and nadir postoperative serum creatinine (post-sCr) were evaluated. In addition, based on our results in combination with detailed data from the literature, a predictive equation for postoperative serum creatinine (post-sCr) was developed by simple regression analysis and validated using Bland-Altman plots.
  
  
  RESULTS
  Finally, 19 patients were eligible for analysis in this study. The value calculated by subtracting pre-CysC (mg/L) from pre-sCr (mg/dl) had a strong correlation to the decrement of serum creatinine (r = 0.9508, p < 0.0001). We added the data of 16 patients obtained from the literature to our series, which were totally randomized into 2 groups, training set and validation set in a 2:1 ratio (n = 23 and 12, respectively) to develop and validate a predictive equation for post-sCr. The mean difference between the predictive and actual post-sCr, -0.68 mg/dl (95% CI -1.62 to 0.26) in the validation set was within the limits of agreement.
  
  
  CONCLUSIONS
  We showed that the discrepancy between pre-sCr and pre-CysC could predict improvement of renal function after intervention in patients with postrenal AKI.
authors.affiliation: Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, 060-8543, Japan. mtkmatsuki@yahoo.co.jp.|Sapporo Kidney Disease Treatment Forum, Sapporo, Japan. mtkmatsuki@yahoo.co.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Matsuki
authors.affiliation: Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, 060-8543, Japan.|Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, 060-8543, Japan.|Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Maehana
authors.affiliation: Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, 060-8543, Japan.|Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kyoda
authors.affiliation: Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, 060-8543, Japan.|Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Ichihara
authors.affiliation: Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, 060-8543, Japan.|Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Hashimoto
authors.affiliation: Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.|Department of Urology, Sunagawa City Medical Center, Sunagawa, 073-0196, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yanase
authors.affiliation: Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.|Department of Urology, Takikawa Municipal Hospital, Takikawa, 073-0022, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Matsukawa
authors.affiliation: Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.|Department of Urology, Saiseikai Otaru Hospital, Otaru, 047-0008, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Adachi
authors.affiliation: Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, 060-8543, Japan.|Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.|Division of Infection Control, Sapporo Medical University School of Medicine, Sapporo, 060-8543, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Urology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, 060-8543, Japan.|Sapporo Kidney Disease Treatment Forum, Sapporo, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Masumori
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007564:Japan; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D003404:Creatinine
keywords: Creatinine; Cystatin C; Postrenal acute kidney injury; Renal function