title: Interaction of time-varying albumin and phosphorus on mortality in incident dialysis patients.
abstract: OBJECTIVE
  Hypoalbuminemia and hyperphosphatemia have been shown to be strong predictors of mortality in dialysis patients that might not be independent from each other. We prospectively investigated the relationship and interaction between serum albumin and phosphorus with all-cause mortality in an inception cohort of incident dialysis patients.
  
  
  METHODS
  We followed 235 incident dialysis patients in a prospective single-center cohort study (INVOR study) applying a time-dependent Cox proportional hazards model using all measured laboratory values (2887 albumin and 10306 phosphorus values).
  
  
  RESULTS
  Eighty-two patients (35%) died during a median follow-up of 35.1 months. Albumin was inversely associated with mortality (hazard ratio [95% confidence interval]: 0.23 [0.14 to 0.36]; P < 0.001), whereas higher phosphorus concentrations showed a trend to an increasing risk for mortality (hazard ratio 1.57 [95% confidence interval 0.97 to 2.54]; P = 0.07). Importantly, we observed a significant interaction between albumin and phosphorus (P = 0.01). The lowest risk was found with concurrent low phosphorus and high albumin values, whereas risk was increased with either concurrent low phosphorus and low albumin values or high phosphorus and high albumin values.
  
  
  CONCLUSIONS
  In incident dialysis patients the associations of serum phosphorus and albumin concentrations with mortality are modified by each other over time. Phosphorus-lowering interventions that concomitantly can cause a fall in serum albumin level may be harmful and warrant additional studies. If confirmed, epidemiologic studies and therapeutic guidelines aiming for target values should consider this interplay.
authors: Department of Nephrology and Dialysis, Academic Teaching Hospital, Feldkirch, Austria.
authors: Emanuel
authors: E
authors: Zitt
authors: Claudia
authors: C
authors: Lamina
authors: Gisela
authors: G
authors: Sturm
authors: Florian
authors: F
authors: Knoll
authors: Friederike
authors: F
authors: Lins
authors: Otto
authors: O
authors: Freistätter
authors: Florian
authors: F
authors: Kronenberg
authors: Karl
authors: K
authors: Lhotta
authors: Ulrich
authors: U
authors: Neyer
mesh_terms: D000368:Aged; D001317:Austria / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D054559:Hyperphosphatemia / Q000097:blood / Q000401:mortality*; D034141:Hypoalbuminemia / Q000097:blood / Q000401:mortality*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000401:mortality* / Q000628:therapy*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010758:Phosphorus / Q000097:blood*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D006435:Renal Dialysis / Q000401:mortality*; D018570:Risk Assessment; D012307:Risk Factors; D012709:Serum Albumin / Q000378:metabolism*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D012709:Serum Albumin; D010758:Phosphorus