International variation in vitamin prescription and association with mortality in the Dialysis Outcomes and Practice Patterns Study (DOPPS).
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.
Fissell
Rachel B
RB
Division of Nephrology, University of Michigan, Ann Arbor, MI, USA. rfissell@umich.edu
Bragg-Gresham
Jennifer L
JL
Gillespie
Brenda W
BW
Goodkin
David A
DA
Bommer
Juergen
J
Saito
Akira
A
Akiba
Takashi
T
Port
Friedrich K
FK
Young
Eric W
EW
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
D001798:Blood Proteins; D014815:Vitamins; D014867:Water