title: Facility Dialysate Calcium Practices and Clinical Outcomes Among Patients Receiving Hemodialysis: A Retrospective Observational Study.
abstract: BACKGROUND
  Some US dialysis facilities have reduced default dialysate calcium concentrations from 2.5 mEq/L to lower levels. There has been no rigorous systematic examination of the effects of such a reduction on clinical and biochemical outcomes.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Medicare-eligible patients who received in-center hemodialysis at a large dialysis organization in January 2008 to December 2010.
  
  
  METHODS
  Facility conversion from predominant use (≥75% patients) of 2.50-mEq/L dialysate calcium to predominant use of lower dialysate calcium concentrations versus maintenance of predominant use of 2.50-mEq/L dialysate calcium.
  
  
  RESULTS
  All-cause and cause-specific mortality and hospitalization, laboratory markers of metabolic bone disease, and drug utilization.
  
  
  METHODS
  Hierarchical mixed linear and Poisson models were fit to compare pre- to postconversion differences in outcomes between converter and matched control facilities. Results, expressed as relative rate ratios (RRRs) and delta-delta (change in mean values), were estimated for early (months 0-2) and late (months 3-12) postconversion to allow for possible latent effects.
  
  
  RESULTS
  Facility conversion was associated with greater rates of hospitalization for heart failure exacerbation (late RRR, 1.27 [95% CI, 1.06-1.51]), hypocalcemia (early RRR, 1.19 [95% CI, 1.05-1.35]; late RRR, 1.39 [95% CI, 1.20-1.60]), and intradialytic hypotension (early RRR, 1.07 [95% CI, 1.02-1.11]; late RRR, 1.05 [95% CI, 1.01-1.10]), but no differences were observed for all-cause mortality or hospitalization rates. Facility conversion was also associated with comparative temporal decreases in serum calcium level, increases in serum phosphate and parathyroid hormone levels, and increases in use of phosphate binders, vitamin D, and calcimimetics.
  
  
  CONCLUSIONS
  Possible residual confounding, generalizability beyond Medicare patients uncertain.
  
  
  CONCLUSIONS
  There are potential safety concerns associated with the default use of dialysate calcium concentrations < 2.50 mEq/L, as well as biochemical evidence of poorer disease control despite associated greater medication use. Individualization of dialysate calcium concentration rather than predominant use of dialysate calcium concentrations < 2.50 mEq/L should be considered.
authors.affiliation: DaVita Clinical Research, Minneapolis, MN. Electronic address: steven.brunelli@davita.com.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Brunelli
authors.affiliation: DaVita Clinical Research, Minneapolis, MN.
authors.forename: Scott
authors.initials: S
authors.lastname: Sibbel
authors.affiliation: AMGEN Inc, Thousand Oaks, CA.
authors.forename: Thy P
authors.initials: TP
authors.lastname: Do
authors.affiliation: AMGEN Inc, Thousand Oaks, CA.
authors.forename: Kerry
authors.initials: K
authors.lastname: Cooper
authors.affiliation: AMGEN Inc, Thousand Oaks, CA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Bradbury
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000032:analysis* / Q000097:blood; D002423:Cause of Death; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000209:etiology / Q000401:mortality; D015312:Hemodialysis Solutions / Q000009:adverse effects* / Q000737:chemistry; D006436:Hemodialysis Units, Hospital; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000401:mortality* / Q000628:therapy; D016014:Linear Models; D008297:Male; D006278:Medicare; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology / Q000401:mortality; D016012:Poisson Distribution; D011379:Prognosis; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D020521:Stroke / Q000209:etiology / Q000401:mortality; D016019:Survival Analysis; D016896:Treatment Outcome; D014481:United States
chemical_list: D015415:Biomarkers; D015312:Hemodialysis Solutions; D002118:Calcium
keywords: End-stage renal disease (ESRD); dialysate calcium concentration; dialysate composition; heart failure; hypocalcemia; intradialytic hypertension; metabolic bone disease; mortality; secondary hyperparathyroidism