Higher convection volume exchange with online hemodiafiltration is associated with survival advantage for dialysis patients: the effect of adjustment for body size.
Mortality remains high for hemodialysis patients. Online hemodiafiltration (OL-HDF) removes more middle-sized uremic toxins but outcomes of individual trials comparing OL-HDF with hemodialysis have been discrepant. Secondary analyses reported higher convective volumes, easier to achieve in larger patients, and improved survival. Here we tested different methods to standardize OL-HDF convection volume on all-cause and cardiovascular mortality compared with hemodialysis. Pooled individual patient analysis of four prospective trials compared thirds of delivered convection volume with hemodialysis. Convection volumes were either not standardized or standardized to weight, body mass index, body surface area, and total body water. Data were analyzed by multivariable Cox proportional hazards modeling from 2793 patients. All-cause mortality was reduced when the convective dose was unstandardized or standardized to body surface area and total body water; hazard ratio (95% confidence intervals) of 0.65 (0.51-0.82), 0.74 (0.58-0.93), and 0.71 (0.56-0.93) for those receiving higher convective doses. Standardization by body weight or body mass index gave no significant survival advantage. Higher convection volumes were generally associated with greater survival benefit with OL-HDF, but results varied across different ways of standardization for body size. Thus, further studies should take body size into account when evaluating the impact of delivered convection volume on mortality end points.
University College London, Centre for Nephrology, Royal Free Hospital, University College London Medical School, London, UK. Electronic address: andrewdavenport@nhs.uk.
Andrew
A
Davenport
The George Institute for Global Health, Nuffield Department of Population Health, University of Oxford, Oxford, UK; Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.
Sanne A E
SA
Peters
Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.
Michiel L
ML
Bots
Nephrology, Dialysis and Intensive Care Unit, Dialysis Research and Training Institute, CHRU, Montpellier, France; Dialysis Research and Training Institute, Montpellier, France.
Bernard
B
Canaud
Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands.
Muriel P C
MP
Grooteman
Division of Nephrology, Ege University School of Medicine, Izmir, Turkey.
Gulay
G
Asci
Department of Nephrology, Alessandro Manzoni Hospital, Lecco, Italy.
Francesco
F
Locatelli
Department of Nephrology, Hospital Clinic, Barcelona, Spain.
Francisco
F
Maduell
Dialysis Research and Training Institute, Montpellier, France; Biochemistry Laboratory, University of Montpellier, CHRU, Montpellier, France.
Marion
M
Morena
Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands.
Menso J
MJ
Nubé
Division of Nephrology, Ege University School of Medicine, Izmir, Turkey.
Ercan
E
Ok
Biostatistics Unit, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain; Biostatistics and Data Management Platform, IDIBAPS, Hospital Clinic, Barcelona, Spain.
Ferran
F
Torres
University College London, Centre for Nephrology, Royal Free Hospital, University College London Medical School, London, UK; The George Institute for Global Health, Nuffield Department of Population Health, University of Oxford, Oxford, UK; Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland, USA.
Mark
M
Woodward
Department of Nephrology, University Medical Center Utrecht, Utrecht, The Netherlands.
Peter J
PJ
Blankestijn
D000368:Aged; D015992:Body Mass Index; D001830:Body Surface Area; D001834:Body Water; D001835:Body Weight; D002318:Cardiovascular Diseases / Q000401:mortality*; D002423:Cause of Death; D018481:Convection; D005260:Female; D017583:Hemodiafiltration / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D051436:Renal Insufficiency, Chronic / Q000401:mortality* / Q000628:therapy*; D015996:Survival Rate
Kt/V; body composition; body mass index; body surface area; hemodiafiltration; total body water