title: Infection risk with bolus versus maintenance iron supplementation in hemodialysis patients.
abstract: Intravenous iron may promote bacterial growth and impair host defense, but the risk of infection associated with iron supplementation is not well defined. We conducted a retrospective cohort study of hemodialysis patients to compare the safety of bolus dosing, which provides a large amount of iron over a short period of time on an as-needed basis, with maintenance dosing, which provides smaller amounts of iron on a regular schedule to maintain iron repletion. Using clinical data from 117,050 patients of a large US dialysis provider merged with data from Medicare's ESRD program, we estimated the effects of iron dosing patterns during repeated 1-month exposure periods on risks of mortality and infection-related hospitalizations during the subsequent 3 months. Of 776,203 exposure/follow-up pairs, 13% involved bolus dosing, 49% involved maintenance dosing, and 38% did not include exposure to iron. Multivariable additive risk models found that patients receiving bolus versus maintenance iron were at increased risk of infection-related hospitalization (risk difference [RD], 25 additional events/1000 patient-years; 95% confidence interval [CI], 16 to 33) during follow-up. Risks were largest among patients with a catheter (RD, 73 events/1000 patient-years; 95% CI, 48 to 99) and a recent infection (RD, 57 events/1000 patient-years; 95% CI, 19 to 99). We also observed an association between bolus dosing and infection-related mortality. Compared with no iron, maintenance dosing did not associate with increased risks for adverse outcomes. These results suggest that maintenance iron supplementation may result in fewer infections than bolus dosing, particularly among patients with a catheter.
authors.affiliation: Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599, USA. mabrook@Email.unc.edu
authors.forename: M Alan
authors.initials: MA
authors.lastname: Brookhart
authors.forename: Janet K
authors.initials: JK
authors.lastname: Freburger
authors.forename: Alan R
authors.initials: AR
authors.lastname: Ellis
authors.forename: Lily
authors.initials: L
authors.lastname: Wang
authors.forename: Wolfgang C
authors.initials: WC
authors.lastname: Winkelmayer
authors.forename: Abhijit V
authors.initials: AV
authors.lastname: Kshirsagar
mesh_terms: D000368:Aged; D015331:Cohort Studies; D019587:Dietary Supplements / Q000009:adverse effects*; D005260:Female; D006760:Hospitalization; D006801:Humans; D007239:Infections / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D007501:Iron / Q000008:administration & dosage / Q000009:adverse effects*; D007676:Kidney Failure, Chronic / Q000401:mortality / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000009:adverse effects*; D012189:Retrospective Studies; D012306:Risk; D018570:Risk Assessment; D015996:Survival Rate; D014481:United States
chemical_list: D007501:Iron