title: Glomerular filtration rate is superior to serum creatinine for prediction of mortality after thoracoabdominal aortic surgery.
abstract: BACKGROUND
  Clinically evident renal disease (dialysis, history of renal insufficiency, or serum creatinine >2.0 mg/dL) is a known risk factor for mortality after thoracoabdominal aortic aneurysm repair. We extended this concept to the questions of whether subclinical renal disease is also a risk factor and how best to identify subclinical disease. We hypothesized that the glomerular filtration rate (GFR) would be a more sensitive determinant of renal function than serum creatinine alone.
  
  
  METHODS
  Between 1991 and 2004, we repaired 1106 thoracoabdominal aortic aneurysms and descending thoracic aortic aneurysms. The median age was 67 years. There were 400 (36%) women and 706 (64%) men. We estimated GFR by using the Cockcroft-Gault equation. We divided baseline serum creatinine and baseline GFR into quartiles and estimated the association of the quartiles with 30-day postoperative mortality by chi2 testing. We further subdivided the population into patients with and without clinically evident renal disease and repeated the analysis in the patients without clinically apparent disease (n = 869).
  
  
  RESULTS
  Clinically apparent renal disease was highly associated with 30-day mortality (odds ratio, 3.2; P < .0001). In all patients, serum creatinine quartile and GFR quartile were also both highly significantly associated with 30-day mortality (P < .0001). In patients without clinically apparent renal disease, both creatinine and GFR predicted additional mortality, but GFR was a much stronger predictor (P < .02 for creatinine vs < .0001 for GFR). In these patients, mortality ranged from 5% in the best GFR quartile to 27% in the worst. Taken as continuous variables in logistic regression equations, serum creatinine had no discrimination in patients without clinical disease (P = .73), whereas GFR remained strong (P < .0001).
  
  
  CONCLUSIONS
  Preoperative renal function is an important determinant of early mortality even in patients without clinically evident disease. Estimated GFR is a much more powerful determinant of mortality risk than serum creatinine alone.
authors.affiliation: Department of Cardiothoracic and Vascular Surgery, The University of Texas at Houston Medical School, Memorial Hermann Hospital, 77030, USA.
authors.forename: Tam T T
authors.initials: TT
authors.lastname: Huynh
authors.forename: Randolph G Statius
authors.initials: RG
authors.lastname: van Eps
authors.forename: Charles C
authors.initials: CC
authors.lastname: Miller
authors.forename: Martin A
authors.initials: MA
authors.lastname: Villa
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Estrera
authors.forename: Ali
authors.initials: A
authors.lastname: Azizzadeh
authors.forename: Eyal E
authors.initials: EE
authors.lastname: Porat
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Goodrick
authors.forename: Hazim J
authors.initials: HJ
authors.lastname: Safi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000453:epidemiology / Q000401:mortality* / Q000601:surgery*; D017545:Aortic Aneurysm, Thoracic / Q000453:epidemiology / Q000401:mortality* / Q000601:surgery*; D002648:Child; D015897:Comorbidity; D003404:Creatinine / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D017052:Hospital Mortality; D006801:Humans; D007674:Kidney Diseases / Q000453:epidemiology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors; D016019:Survival Analysis
chemical_list: D003404:Creatinine