title: Vitamin D does not improve the metabolic health of patients with chronic kidney disease stage 3-4: a randomized controlled trial.
abstract: OBJECTIVE
  To assess the impact of vitamin D supplementation (cholecalciferol) on the insulin sensitivity and metabolic health of patients with chronic kidney disease (CKD).
  
  
  METHODS
  Twenty-eight adult patients with CKD stages 3-4 were recruited from the outpatient department of the Princess Alexandra Hospital (Brisbane, Australia) to a double-blind randomized trial of cholecalciferol (vitamin D3) 2000 IU/day or placebo for 6 months. Metabolic parameters at baseline were compared with 20 non-CKD adults. The primary outcome was an improvement in insulin resistance (glucose disposal rate, GDR) at 6 months (quantified by hyperinsulinaemic euglycaemic clamp). Carbohydrate and lipid oxidation rates were assessed by indirect calorimetry.
  
  
  RESULTS
  At baseline, patients were significantly insulin-resistant compared with lean younger non-CKD individuals (n = 9; GDR 3.42 vs. 5.76 mg/kg per minute, P = 0.001), but comparable with their age-, gender- and weight-matched non-CKD counterparts (n = 11; 3.42 vs. 3.98 mg/kg per minute, P = 0.4). 25-Hydroxyvitamin D did not change in the placebo group, but rose from 95 ± 37 to 146 ± 25 nmol/L with treatment (P = 0.0001). Post treatment, there was no difference in GDR between groups (GDR 3.38 vs. 3.52 mg/kg per minute, ancova P = 0.4). There was a relative increase in hyperinsulinaemic oxidative disposal of glucose with treatment (within-group P = 0.03).
  
  
  CONCLUSIONS
  Supplementation with cholecalciferol in CKD 3-4 results in appreciable increases in 25-hydroxyvitamin D concentrations, but does not increase insulin sensitivity. The insulin resistance observed was similar among age-, sex- and body mass index-matched individuals with and without CKD. Whether renal dysfunction per se has any influence on the insulin sensitivity of an individual should be the subject of future work.
authors.affiliation: Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.
authors.forename: William G
authors.initials: WG
authors.lastname: Petchey
authors.forename: Ingrid J
authors.initials: IJ
authors.lastname: Hickman
authors.forename: Johannes B
authors.initials: JB
authors.lastname: Prins
authors.forename: Carmel M
authors.initials: CM
authors.lastname: Hawley
authors.forename: David W
authors.initials: DW
authors.lastname: Johnson
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Isbel
authors.forename: Emma L
authors.initials: EL
authors.lastname: Duncan
mesh_terms: D000368:Aged; D002762:Cholecalciferol / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008659:Metabolic Diseases / Q000188:drug therapy* / Q000209:etiology; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000378:metabolism*; D012720:Severity of Illness Index; D017211:Treatment Failure; D014815:Vitamins / Q000627:therapeutic use*
chemical_list: D014815:Vitamins; D002762:Cholecalciferol