title: International variation in vitamin prescription and association with mortality in the Dialysis Outcomes and Practice Patterns Study (DOPPS).
abstract: BACKGROUND
  The prevalence of water-soluble vitamin use among hemodialysis (HD) patients and whether mortality and hospitalization are associated with water-soluble vitamin use by HD patients have not previously been reported. The present study investigates patterns of water-soluble vitamin use among HD patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS) I and evaluates outcomes associated with vitamin use.
  
  
  METHODS
  The study sample came from the DOPPS I, a prospective observational study of adult HD patients (N = 16,345) randomly selected from 308 representative dialysis facilities in France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States. Time-dependent Cox regression models were used to assess relative risk (RR) for mortality and hospitalization for patients administered water-soluble vitamins versus those not administered water-soluble vitamins.
  
  
  RESULTS
  There was large variation by region in the percentage of patients administered water-soluble vitamins: Europe ranged from a low of 3.7% in the United Kingdom to a high of 37.9% in Spain; 5.6% in Japan; and 71.9% in the United States. Patient use of water-soluble vitamins was associated with a substantially and significantly lower risk for mortality (RR, 0.84; P = 0.001). Lower RR for facility-level mortality also was associated with greater water-soluble vitamin use (RR, 0.98; P = 0.05 per 10% more patients administered water-soluble vitamins at the facility).
  
  
  CONCLUSIONS
  Although only a randomized trial could prove that water-soluble vitamins improve outcomes, use of water-soluble vitamins is a minimal-risk practice pattern associated with improved outcomes in this prospective observational study.
authors.affiliation: Division of Nephrology, University of Michigan, Ann Arbor, MI, USA. rfissell@umich.edu
authors.forename: Rachel B
authors.initials: RB
authors.lastname: Fissell
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Bragg-Gresham
authors.forename: Brenda W
authors.initials: BW
authors.lastname: Gillespie
authors.forename: David A
authors.initials: DA
authors.lastname: Goodkin
authors.forename: Juergen
authors.initials: J
authors.lastname: Bommer
authors.forename: Akira
authors.initials: A
authors.lastname: Saito
authors.forename: Takashi
authors.initials: T
authors.lastname: Akiba
authors.forename: Friedrich K
authors.initials: FK
authors.lastname: Port
authors.forename: Eric W
authors.initials: EW
authors.lastname: Young
mesh_terms: D000328:Adult; D000368:Aged; D001798:Blood Proteins / Q000032:analysis; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D004363:Drug Utilization / Q000706:statistics & numerical data; D005060:Europe / Q000453:epidemiology; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D006435:Renal Dialysis / Q000401:mortality*; D012306:Risk; D012494:Sampling Studies; D012995:Solubility; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D014815:Vitamins / Q000008:administration & dosage* / Q000737:chemistry; D014867:Water
chemical_list: D001798:Blood Proteins; D014815:Vitamins; D014867:Water