title: Dose-response effect of ergocalciferol therapy on serum 25-hydroxyvitamin D concentration during critical illness.
abstract: OBJECTIVE
  The aim of this study was to evaluate the dose-response relationship between ergocalciferol therapy and serum 25-hydroxyvitamin D concentrations in enterally fed, critically ill patients with traumatic injuries.
  
  
  METHODS
  A retrospective cohort of critically ill patients with traumatic injuries and vitamin D deficiency (25-OH vitamin D <50 nmol/L) were given either 50 000 IU of liquid ergocalciferol weekly, twice weekly, or three times weekly while in the intensive care unit (ICU). Serum 25-OH vitamin D and ionized calcium concentrations were monitored weekly. Ergocalciferol therapy was stopped when the serum 25-OH vitamin D was >75 nmol/L, if the patient experienced hypercalcemia (ionized calcium >1.34 mmol/L), when the patient was discharged from the ICU, or if enteral nutrition was discontinued.
  
  
  RESULTS
  Sixty-five patients (16, 18, and 31 per dosage group) were examined. One (6%), two (11%), and eight (26%) patients achieved normal 25-OH vitamin D concentrations after 2 to 4 wk of ergocalciferol therapy for each dosage group, respectively (P < 0.001). Serum 25-OH vitamin D concentrations improved from 36 ± 6, 40 ± 7, and 37 ± 6 nmol/L to 50 ± 15, 54 ± 21, and 62 ± 17 nmol/L, respectively, after 2 wk of ergocalciferol therapy (P < 0.001) Two (13%), one (6%), and seven (23%) patients developed hypercalcemia for each dosage group, respectively (P = NS).
  
  
  CONCLUSIONS
  Ergocalciferol therapy improved baseline serum 25-OH vitamin D concentrations but was inadequate for consistently achieving normal serum concentrations of 25-OH vitamin D during critical illness. The trend in increasing appearance of mild hypercalcemia for the highest dosage group is concerning.
authors.affiliation: Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA. Electronic address: Rdickerson@uthsc.edu.
authors.forename: Roland N
authors.initials: RN
authors.lastname: Dickerson
authors.affiliation: Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Scott C
authors.initials: SC
authors.lastname: Berry
authors.affiliation: Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Jamie D
authors.initials: JD
authors.lastname: Ziebarth
authors.affiliation: Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Swanson
authors.affiliation: Department of Surgery, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: George O
authors.initials: GO
authors.lastname: Maish
authors.affiliation: Department of Surgery, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Gayle
authors.initials: G
authors.lastname: Minard
authors.affiliation: Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Rex O
authors.initials: RO
authors.lastname: Brown
mesh_terms: D000328:Adult; D000368:Aged; D002118:Calcium / Q000097:blood; D016638:Critical Illness / Q000628:therapy*; D004305:Dose-Response Relationship, Drug; D004750:Enteral Nutrition / Q000379:methods; D004872:Ergocalciferols / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy*; D014815:Vitamins / Q000008:administration & dosage*; D014947:Wounds and Injuries / Q000097:blood
chemical_list: D004872:Ergocalciferols; D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium
keywords: Calcium; Cholecalciferol; Enteral nutrition; Ergocalciferol; Injury; Trauma; Vitamin D