ASN's Mission

To create a world without kidney diseases, the ASN Alliance for Kidney Health elevates care by educating and informing, driving breakthroughs and innovation, and advocating for policies that create transformative changes in kidney medicine throughout the world.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005


The Latest on X

Kidney Week

Please note that you are viewing an archived section from 2022 and some content may be unavailable. To unlock all content for 2022, please visit the archives.

Abstract: SA-PO355

Percent of Patients That Exceed Candidate Ultrafiltration Rate (UFR) Warning Levels Based on 3 Different Scaling Approaches (Unscaled UFR, UFR per kg, or UFR per kg^0.4)

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • Mermelstein, Ariella E., Renal Research Institute, New York, New York, United States
  • Daugirdas, John T., University of Illinois Chicago College of Medicine, Chicago, Illinois, United States
  • Raimann, Jochen G., Renal Research Institute, New York, New York, United States
  • Wang, Yuedong, University of California Santa Barbara, Santa Barbara, California, United States
  • Kotanko, Peter, Renal Research Institute, New York, New York, United States

Exceeding a UFR warning level of 13 ml/h per kg is associated with higher mortality hazard ratios (MHR) in large patients (KI Reports, 2022) while exceeding UFR warning levels not scaled to body size is less affected by body weight. UFRs associated with an MHR of 1.0 (average risk) can be estimated as 105 x kg^0.40 ml/hr. Thus, a new candidate UFR warning level might be set 33% (140/105) higher: 140 x kg^0.40 (ml/hr).


This retrospective cohort study was performed on 2542 incident U.S. hemodialysis (HD) patients. We examined the prevalence (12-mo average) of exceeded UFR warning levels: 800 m/h, 10 ml/h per kg, or140 x kg^0.40. Each warning level was associated with an MHR of 1.2 for an 80 kg patient.


The estimated MHRs when exceeding each warning level are shown in the Table. The percent patients exceeding each warning level by weight decile is shown in the figure. Most patients exceeding the UFR/kg warning were smaller, while patients exceeding 800 ml/h were larger. A UFR warning based on 40 x kg^0.4 ml/hr was exceeded in about 15% of patients across a broad spectrum of body weight.


The percentage of patients exceeding unscaled UFR or UFR/kg warning levels is highly dependent on body weight. Warnings scaled by UFR/kg^0.4 may be more practical to implement, as they are exceeded by similar percentages of patients of different sizes; however, MHRs associated with exceeding UFR/kg^0.4 scaled warning levels still vary somewhat with body weight.

Weight (kg)800 ml/h140 x kg^0.410 ml/h per kg800 ml/h140 x kg^0.410 ml/h per kg
 4-h max. weight removal (kg)Mortality Hazard Ratio (MHR)