title: The relationship between hypophosphataemia and outcomes during low-intensity and high-intensity continuous renal replacement therapy.
abstract: OBJECTIVE
  To identify risk factors for development of hypophosphataemia in patients treated with two different intensities of continuous renal replacement therapy (CRRT) and to assess the independent association of hypophosphataemia with major clinical outcomes.
  
  
  METHODS
  We performed secondary analysis of data collected from 1441 patients during a large, multicentre randomised controlled trial of CRRT intensity. We allocated patients to two different intensities of CRRT (25mL/kg/hour vs 40 mL/kg/hour of effluent generation) and obtained daily measurement of serum phosphate levels.
  
  
  RESULTS
  We obtained 14 115 phosphate measurements and identified 462 patients (32.1%) with hypophosphataemia, with peak incidence on Day 2 and Day 3. With lower intensity CRRT, there were 58 episodes of hypophosphataemia/1000 patient days, compared with 112 episodes/1000 patient days with higher intensity CRRT (P < 0.001). On multivariable logistic regression analysis, higher intensity CRRT, female sex, higher Acute Physiology and Chronic Health Evaluation score and hypokalaemia were independently associated with an increased odds ratio (OR) for hypophosphataemia. On multivariable models, hypophosphataemia was associated with better clinical outcomes, but when analysis was confined to patients alive at 96 hours, hypophosphataemia was not independently associated with clinical outcomes.
  
  
  CONCLUSIONS
  Hypophosphataemia is common during CRRT and its incidence increases with greater CRRT intensity. Hypophosphataemia is not a robust independent predictor of mortality. Its greater incidence in the higher intensity CRRT arm of the Randomised Evaluation of Normal vs Augmented Level trial does not explain the lack of improved outcomes with such treatment.
authors.affiliation: Australian and New Zealand Intensive Care Research Centre, Melbourne, VIC, Australia.
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Bellomo
authors.affiliation: Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia.
authors.forename: Alan
authors.initials: A
authors.lastname: Cass
authors.affiliation: Intensive Care Unit, Nepean Hospital, Sydney, NSW, Australia.
authors.forename: Louise
authors.initials: L
authors.lastname: Cole
authors.affiliation: Intensive Care Department, Royal North Shore Hospital, Sydney, NSW, Australia.
authors.forename: Simon
authors.initials: S
authors.lastname: Finfer
authors.affiliation: The George Institute for Global Health, Sydney, NSW, Australia.
authors.forename: Martin
authors.initials: M
authors.lastname: Gallagher
authors.affiliation: Intensive Care Unit, Austin Hospital, Melbourne, VIC, Australia.
authors.forename: Inbyung
authors.initials: I
authors.lastname: Kim
authors.affiliation: The George Institute for Global Health, Sydney, NSW, Australia.
authors.forename: Joanne
authors.initials: J
authors.lastname: Lee
authors.affiliation: The George Institute for Global Health, Sydney, NSW, Australia.
authors.forename: Serigne
authors.initials: S
authors.lastname: Lo
authors.affiliation: Auckland City Hospital, Auckland, New Zealand.
authors.forename: Colin
authors.initials: C
authors.lastname: McArthur
authors.forename: Shay
authors.initials: S
authors.lastname: McGuinness
authors.affiliation: Auckland City Hospital, Auckland, New Zealand.
authors.forename: Shay
authors.initials: S
authors.lastname: McGuiness
authors.affiliation: The George Institute for Global Health, Sydney, NSW, Australia.
authors.forename: Robyn
authors.initials: R
authors.lastname: Norton
authors.affiliation: The George Institute for Global Health, Sydney, NSW, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Myburgh
authors.affiliation: Department of Intensive Care, Alfred Hospital, Melbourne, VIC, Australia.
authors.forename: Carlos
authors.initials: C
authors.lastname: Scheinkestel
mesh_terms: D000328:Adult; D001315:Australia / Q000453:epidemiology; D016638:Critical Illness / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017674:Hypophosphatemia / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D015994:Incidence; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D010710:Phosphates / Q000097:blood*; D011379:Prognosis; D017582:Renal Replacement Therapy / Q000379:methods*; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends
chemical_list: D010710:Phosphates