Nephrology Dialysis Transplantation

Effect of hemodiafiltration on measured physical activity: primary results of the HDFIT randomized controlled trial.

Roberto Pecoits-Filho, John W. Larkin, Carlos Eduardo Poli-de-Figueiredo, Américo Lourenço Cuvello-Neto, Ana Beatriz Lesqueves Barra, Priscila Bezerra Gonçalves, Shimul Sheth, Murilo Guedes, Maggie Han, Viviane Calice-Silva, Manuel Carlos Martins de Castro, Peter Kotanko, Thyago Proenca de Moraes, Jochen G Raimann, Maria Eugenia F Canziani, the HDFIT Study Investigators

Background: Dialysis patients are typically inactive and their physical activity (PA) decreases over time. Uremic toxicity has been suggested as a potential causal factor of low PA in dialysis patients. Post-dilution high-volume online hemodiafiltration (HDF) provides greater higher molecular weight removal and studies suggest better clinical/patient-reported outcomes compared with hemodialysis (HD).

Methods: HDFIT was a randomized controlled trial at 13 clinics in Brazil that aimed to investigate the effects of HDF on measured PA (step counts) as a primary outcome. Stable HD patients (vintage 3-24 months) were randomized to receive HDF or high-flux HD. Treatment effect of HDF on the primary outcome from baseline to 3 and 6 months was estimated using a linear mixed-effects model.

Results: We randomized 195 patients (HDF 97; HD 98) between August 2016 and October 2017. Despite the achievement of a high convective volume in the majority of sessions and a positive impact on solute removal, the treatment effect HDF on the primary outcome was +538 [95% confidence interval (CI) -330 to 1407] steps/24 h after dialysis compared with HD, and was not statistically significant. Despite a lack of statistical significance, the observed size of the treatment effect was modest and driven by steps taken between 1.5 and 24.0 h after dialysis, in particular between 20 and 24 h (+197 steps; 95% CI -95 to 488).

Conclusions: HDF did not have a statistically significant treatment effect on PA 24 h following dialysis, albeit effect sizes may be clinically meaningful and deserve further investigation.

About the Contributors

Maggie Han, MSc

Research Scientist 

Maggie has a bachelor’s degree from New York University, where she studied economics and has a master’s degree in health sciences from Pontifícia Universidade Católica do Paraná. She is the executive assistant to Dr. Peter Kotanko, Research Director. In addition to her administrative duties, she is also very active in research. Her work is mainly focused on pervasive sensing techniques, wearables, and study of physical activity, sleep, and patient-reported outcomes in chronic kidney disease patients.

Dr. Peter Kotanko, MD

RRI Research Director

SVP, Corporate Research & Development

Peter Kotanko, MD, is Research Director at the Renal Research Institute (RRI), New York. Prior to joining RRI, from 1997 to 2007 he served as vice chair of a department of internal medicine at an academic teaching hospital in Graz, Austria. Prior to moving to Graz in 1989, he worked from 1982 to 1989 in the Department of Physiology and the University Clinic of Internal Medicine in Innsbruck, Austria. From 1995 to 1996 he trained in nephrology at the Hammersmith Hospital, London, United Kingdom.

Jochen G. Raimann, MD, PhD, MPH

Senior Manager, Clinical Data Analytics

Jochen has worked as a full-time scientist at RRI since his start as a postdoctoral research fellow in 2007. As Senior Manager of Clinical Data Analytics, Jochen conducts epidemiological research in dialysis and oversees many analytical projects. He has first- and co-authored numerous papers and also serves as Associate Editor of the journals Trials and Scientific Reports. Jochen earned his MD from the Medical University Graz, his PhD from Maastricht University...