title: Risk in dosing regimens for 25-OH vitamin D supplementation in chronic haemodialysis patients.
abstract: BACKGROUND
  25-OH vitamin D (25-OHvitD) insufficiency or deficiency should be treated in haemodialysis (HD) patients, although the 25-OHvitD target, drug or dosing regimens are unclear.
  
  
  OBJECTIVE
  To describe factors associated with 25-OHvitD levels in HD patients and to assess the effect of three dosing regimens to supplement 25-OHvitD (calcifediol) on serum calcium (Ca), phosphate (P), parathyroid hormone (PTH), 25-OHvitD and 1,25-OHvitD.
  
  
  METHODS
  Two hundred and seventeen patients from three HD units were studied. Demographic and biochemical data were collected at baseline. Two different 25-OHvitD assays were used. One hundred and sixty-seven patients were treated with various calcifediol dosing regimens. The same biochemical determinations were repeated after 3 months of treatment.
  
  
  RESULTS
  At baseline, 12.9% of patients had 25-OHvitD <10 ng/ml. In multivariate linear regression, the season (lower in winter) and the assay method were determinants of 25-OHvitD concentration. Following calcifediol supplementation, 25-OHvitD, calcium and phosphate increased, while PTH diminished with statistical significance. After treatment, there were positive correlations between 25-OHvitD and Ca (r = 0.28, p < 0.0001) or 1,25-OHvitD (r = 0.75, p < 0.0001) that were not observed in the baseline dataset. High concentrations of post-treatment 25-OHvitD were associated with higher 1,25-OHvitD levels. Calcemia increased more in those treated with concomitant active vitamin D or those having suppressed baseline PTH, while PTH decreased more in those having above-target PTH levels.
  
  
  CONCLUSIONS
  Standardisation of methods to determine 25-OHvitD blood levels is needed. In HD patients, calcifediol increased 25-OHvitD, calcemia and phosphatemia and lowered PTH. Caution should be exercised with the higher calcifediol dosing regimens, especially in patients with suppressed PTH or on vitamin D receptor activators.
authors.affiliation: Servicio de Nefrología, Hospital Universitario Infanta Leonor, Autonoma University IIS-Fundación Jiménez Díaz, Madrid, Spain. malbalater@senefro.org
authors.forename: M
authors.initials: M
authors.lastname: Albalate
authors.forename: C
authors.initials: C
authors.lastname: de la Piedra
authors.forename: A
authors.initials: A
authors.lastname: Ortiz
authors.forename: J
authors.initials: J
authors.lastname: Hernández Pérez
authors.forename: M
authors.initials: M
authors.lastname: Rubert
authors.forename: R
authors.initials: R
authors.lastname: Pérez Garcia
authors.forename: P
authors.initials: P
authors.lastname: Zazo
authors.forename: L
authors.initials: L
authors.lastname: Nieto
authors.forename: P
authors.initials: P
authors.lastname: de Sequera
authors.forename: J
authors.initials: J
authors.lastname: Egido
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D019587:Dietary Supplements / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D064420:Drug-Related Side Effects and Adverse Reactions / Q000097:blood / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D006801:Humans; D015994:Incidence; D007676:Kidney Failure, Chronic / Q000097:blood / Q000453:epidemiology / Q000534:rehabilitation*; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000706:statistics & numerical data*; D018570:Risk Assessment; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D016896:Treatment Outcome; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology / Q000517:prevention & control*; D055815:Young Adult
chemical_list: D014807:Vitamin D