title: Serum uric acid levels show a 'J-shaped' association with all-cause mortality in haemodialysis patients.
abstract: BACKGROUND
  Although elevated serum levels of uric acid are common in patients with kidney disease or in those receiving maintenance dialysis therapy, the clinical impact of uric acid on mortality in haemodialysis (HD) patients remains unclear. This work was designed to explore the predictive value of serum uric acid levels on all-cause mortality of HD patients.
  
  
  METHODS
  We retrospectively analysed mortality rates in 146 chronic HD patients that were treated with HD three times per week at our HD unit for a period of one full year. The analysed parameters included demographic characteristics, aetiology of end-stage renal disease, co-morbid conditions, duration (at least 1 year) and delivered dose of HD, normalized protein catabolic rate, serum albumin concentration, haematocrit, serum uric acid (UA) levels and other laboratory parameters. A multivariate Cox proportional hazards model, which included adjustment for the above factors, was applied to identify the predictive value of UA levels on patient mortality.
  
  
  RESULTS
  A Cox proportional hazards model revealed that decreased serum albumin, underlying diabetic nephropathy (DMN) and UA groups (< or =20th, 20-80th and > or =80th percentiles; P = 0.016) were all significant, independent predictors of all-cause mortality in HD patients. The hazard ratios of death were: serum albumin (per 0.5 g/dl decrease), 3.10 [95% confidence interval (95% CI), 1.80-5.34, P < 0.001]; DMN (vs non-DMN), 3.47 (95% CI, 1.25-9.59, P = 0.017); and UA groups (vs 20th to 80th percentile): < or =20th percentile, 2.98 (95% CI, 0.82-10.90, P = 0.099); > or = 80th percentile, 5.67 (95% CI, 1.71-18.78, P = 0.004).
  
  
  CONCLUSIONS
  These preliminary observations suggest that HD patients in the lowest and highest quintiles of UA levels would face higher risk of mortality. Further studies with larger sample sizes will be needed to confirm these findings.
authors.affiliation: Department of Internal Medicine, Far Eastern Memorial Hospital and National Taiwan University Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Shih-Ping
authors.initials: SP
authors.lastname: Hsu
authors.forename: Mei-Fen
authors.initials: MF
authors.lastname: Pai
authors.forename: Yu-Sen
authors.initials: YS
authors.lastname: Peng
authors.forename: Chin-Kang
authors.initials: CK
authors.lastname: Chiang
authors.forename: Tai-I
authors.initials: TI
authors.lastname: Ho
authors.forename: Kuan-Yu
authors.initials: KY
authors.lastname: Hung
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D002423:Cause of Death; D002681:China; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006436:Hemodialysis Units, Hospital; D006801:Humans; D007676:Kidney Failure, Chronic / Q000401:mortality* / Q000628:therapy; D007677:Kidney Function Tests; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D011237:Predictive Value of Tests; D011336:Probability; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000379:methods / Q000401:mortality*; D012189:Retrospective Studies; D018570:Risk Assessment; D017678:Sex Distribution; D016019:Survival Analysis; D014527:Uric Acid / Q000097:blood*
chemical_list: D014527:Uric Acid