title: [Impact of pre-operative uric acid on acute kidney injury after cardiac surgery in elderly patients].
abstract: OBJECTIVE
  To investigate the impact of pre-operative uric acid on acute kidney injury (AKI) after cardiac surgery in elderly patients.
  
  
  METHODS
  Clinical data were collected from 936 elderly patients (age ≥ 60 years) undergoing cardiac surgery with cardiopulmonary bypass in Guangdong General Hospital between January 2005 and May 2011. The baseline serum creatinine was defined as the latest serum creatinine before surgery, and AKI was diagnosed according to RIFLE criteria. Patients were divided into three groups according to the sex-specific cutoff values of serum uric acid tertiles (group A: ≤ 384.65 µmol/L in men, and ≤ 354.00 µmol/L in women; group B:384.66-476.99 µmol/L in men and 354.01-437.96 µmol/L in women; group C: ≥ 477.00 µmol/L in men and ≥ 437.97 µmol/L in women). Multivariate logistic regression analysis was used to analyze the independent risk factors for AKI.
  
  
  RESULTS
  Among 936 elderly patients, 576 cases (61.5%) developed AKI. Mean uric acid concentration was higher in AKI patients than in Non-AKI patients ( (436.6 ± 119.1) µmol/L vs. (398.0 ± 107.2) µmol/L, P < 0.001). The incidence of AKI was 56.1% (175/312) in group A, 56.3% (175/311) in group B, 72.2% (226/313) in group C (P < 0.001). Multiple logistic regression analysis showed that, after adjusted for age, gender, co-morbidities(hypertension, diabetes mellitus, cerebrovascular disease, chronic obstructive pulmonary disease), previous cardiac surgery, eGFR<60 ml×min(-1) ×1.73 m(-2), heart function ≥ 3 (NYHA), positive urine protein, combination of coronary artery bypass grafting and valvular surgery, cardiopulmonary bypass operation time, aortic cross-clamping time, pre-operative angiotensin converting enzyme inhibitor or angiotensin II receptor blockers and lipid-lowering drugs use, early postoperative angiotensin converting enzyme inhibitor or angiotensin II receptor blockers, diuretics and digoxin use, post-operation central venous pressure, risk of post operative AKI was significantly higher in group C than in group A (OR:1.897, 95%CI: 1.270-2.833, P = 0.002).
  
  
  CONCLUSIONS
  Pre-operative elevated uric acid is an independent risk factor of AKI after cardiac surgery in elderly patients.
authors.affiliation: Graduate School, Southern Medical University, Guangzhou 510515, China.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Xu
authors.forename: Yuanhan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Email: xinlingliang@139.com.
authors.forename: Xinling
authors.initials: X
authors.lastname: Liang
authors.forename: Penghua
authors.initials: P
authors.lastname: Hu
authors.forename: Lu
authors.initials: L
authors.lastname: Cai
authors.forename: Shengli
authors.initials: S
authors.lastname: An
authors.forename: Zhilian
authors.initials: Z
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology*; D000368:Aged; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D005260:Female; D006801:Humans; D015994:Incidence; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors; D014527:Uric Acid / Q000097:blood*
chemical_list: D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D014527:Uric Acid