title: Mortality and cardiovascular events in online haemodiafiltration (OL-HDF) compared with high-flux dialysis: results from the Turkish OL-HDF Study.
abstract: BACKGROUND
  Online haemodiafiltration (OL-HDF) is considered to confer clinical benefits over haemodialysis (HD) in terms of solute removal in patients undergoing maintenance HD. The aim of this study was to compare postdilution OL-HDF and high-flux HD in terms of morbidity and mortality.
  
  
  METHODS
  In this prospective, randomized, controlled trial, we enrolled 782 patients undergoing thrice-weekly HD and randomly assigned them in a 1:1 ratio to either postdilution OL-HDF or high-flux HD. The mean age of patients was 56.5 ± 13.9 years, time on HD 57.9 ± 44.6 months with a diabetes incidence of 34.7%. The follow-up period was 2 years, with the mean follow-up of 22.7 ± 10.9 months. The primary outcome was a composite of death from any cause and nonfatal cardiovascular events. The major secondary outcomes were cardiovascular and overall mortality, intradialytic complications, hospitalization rate, changes in several laboratory parameters and medications used.
  
  
  RESULTS
  The filtration volume in OL-HDF was 17.2 ± 1.3 L. Primary outcome was not different between the groups (event-free survival of 77.6% in OL-HDF versus 74.8% in the high-flux group, P = 0.28), as well as cardiovascular and overall survival, hospitalization rate and number of hypotensive episodes. In a post hoc analysis, the subgroup of OL-HDF patients treated with a median substitution volume >17.4 L per session (high-efficiency OL-HDF, n = 195) had better cardiovascular (P = 0.002) and overall survival (P = 0.03) compared with the high-flux HD group. In adjusted Cox-regression analysis, treatment with high-efficiency OL-HDF was associated with a 46% risk reduction for overall mortality {RR = 0.54 [95% confidence interval (95% CI) 0.31-0.93], P = 0.02} and a 71% risk reduction for cardiovascular mortality [RR = 0.29 (95% CI 0.12-0.65), P = 0.003] compared with high-flux HD.
  
  
  CONCLUSIONS
  The composite of all-cause mortality and nonfatal cardiovascular event rate was not different in the OL-HDF and in the high-flux HD groups. In a post hoc analysis, OL-HDF treatment with substitution volumes over 17.4 L was associated with better cardiovascular and overall survival.
authors.affiliation: Division of Nephrology, Ege University School of Medicine, Izmir, Turkey. ercan.ok@ege.edu.tr
authors.forename: Ercan
authors.initials: E
authors.lastname: Ok
authors.forename: Gulay
authors.initials: G
authors.lastname: Asci
authors.forename: Huseyin
authors.initials: H
authors.lastname: Toz
authors.forename: Ebru Sevinc
authors.initials: ES
authors.lastname: Ok
authors.forename: Fatih
authors.initials: F
authors.lastname: Kircelli
authors.forename: Mumtaz
authors.initials: M
authors.lastname: Yilmaz
authors.forename: Ender
authors.initials: E
authors.lastname: Hur
authors.forename: Meltem Sezis
authors.initials: MS
authors.lastname: Demirci
authors.forename: Cenk
authors.initials: C
authors.lastname: Demirci
authors.forename: Soner
authors.initials: S
authors.lastname: Duman
authors.forename: Ali
authors.initials: A
authors.lastname: Basci
authors.forename: Siddig Momin
authors.initials: SM
authors.lastname: Adam
authors.forename: Ismet Onder
authors.initials: IO
authors.lastname: Isik
authors.forename: Murat
authors.initials: M
authors.lastname: Zengin
authors.forename: Gultekin
authors.initials: G
authors.lastname: Suleymanlar
authors.forename: Mehmet Emin
authors.initials: ME
authors.lastname: Yilmaz
authors.forename: Mehmet
authors.initials: M
authors.lastname: Ozkahya
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D017583:Hemodiafiltration / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016019:Survival Analysis; D014421:Turkey