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Mermelstein A, Raimann JG, Wang Y, Kotanko P, Daugirdas JT. Ultrafiltration Rate Levels in Hemodialysis Patients Associated with Weight-Specific Mortality Risks. Clin J Am Soc Nephrol 2023; 18:767-776. [PMID: 36913263 PMCID: PMC10278805 DOI: 10.2215/cjn.0000000000000144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 02/27/2023] [Indexed: 03/14/2023]
Abstract
BACKGROUND We hypothesized that the association of ultrafiltration rate with mortality in hemodialysis patients was differentially affected by weight and sex and sought to derive a sex- and weight-indexed ultrafiltration rate measure that captures the differential effects of these parameters on the association of ultrafiltration rate with mortality. METHODS Data were analyzed from the US Fresenius Kidney Care (FKC) database for 1 year after patient entry into a FKC dialysis unit (baseline) and over 2 years of follow-up for patients receiving thrice-weekly in-center hemodialysis. To investigate the joint effect of baseline-year ultrafiltration rate and postdialysis weight on survival, we fit Cox proportional hazards models using bivariate tensor product spline functions and constructed contour plots of weight-specific mortality hazard ratios over the entire range of ultrafiltration rate values and postdialysis weights (W). RESULTS In the studied 396,358 patients, the average ultrafiltration rate in ml/h was related to postdialysis weight (W) in kg: 3W+330. Ultrafiltration rates associated with 20% or 40% higher weight-specific mortality risk were 3W+500 and 3W+630 ml/h, respectively, and were 70 ml/h higher in men than in women. Nineteen percent or 7.5% of patients exceeded ultrafiltration rates associated with a 20% or 40% higher mortality risk, respectively. Low ultrafiltration rates were associated with subsequent weight loss. Ultrafiltration rates associated with a given mortality risk were lower in high-body weight older patients and higher in patients on dialysis for more than 3 years. CONCLUSIONS Ultrafiltration rates associated with various levels of higher mortality risk depend on body weight, but not in a 1:1 ratio, and are different in men versus women, in high-body weight older patients, and in high-vintage patients.
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Affiliation(s)
- Ariella Mermelstein
- Renal Research Institute, New York, New York
- Katz School of Science and Health at Yeshiva University, New York, New York
| | - Jochen G. Raimann
- Renal Research Institute, New York, New York
- Katz School of Science and Health at Yeshiva University, New York, New York
| | - Yuedong Wang
- University of California—Santa Barbara, Santa Barbara, California
| | - Peter Kotanko
- Renal Research Institute, New York, New York
- Icahn School of Medicine at Mount Sinai, New York, New York
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Schmiedecker M, Krenn S, Waller M, Paschen C, Mussnig S, Niknam J, Wabel P, Mayer CC, Hecking M, Schneditz D. Ultrafiltration-induced decrease in relative blood volume is larger in hemodialysis patients with low specific blood volume: Results from a dialysate bolus administration study. Hemodial Int 2023; 27:174-183. [PMID: 36703281 DOI: 10.1111/hdi.13066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 11/04/2022] [Accepted: 01/10/2023] [Indexed: 01/28/2023]
Abstract
INTRODUCTION Prescribing the ultrafiltration in hemodialysis patients remains challenging and might benefit from the information on absolute blood volume, estimated by intradialytic dialysate bolus administration. Here, we aimed at determining the relationship between absolute blood volume, normalized for body mass (specific blood volume, Vs), and ultrafiltration-induced decrease in relative blood volume (∆RBV) as well as clinical parameters including body mass index (BMI). METHODS This retrospective analysis comprised 77 patients who had their dialysate bolus-based absolute blood volume extracted routinely with an automated method. Patient-specific characteristics and ∆RBV were analyzed as a function of Vs, dichotomizing the data above or below a previously proposed threshold of 65 ml/kg for Vs. Statistical methodology comprised descriptive analyses, two-group comparisons, and correlation analyses. FINDINGS Median Vs was 68.6 ml/kg (54.9 ml/kg [Quartile 1], 83.4 ml/kg [Quartile 3]). Relative blood volume decreased by 6.3% (2.6%, 12.2%) over the entire hemodialysis session. Vs correlated inversely with BMI (rs = -0.688, p < 0.001). ∆RBV was 9.8% in the group of patients with Vs <65 ml/kg versus 6.0% in the group of patients with Vs ≥65 ml/kg (p = 0.024). The two groups did not differ significantly regarding their specific ultrafiltration volume, normalized for body mass, which amounted to 34.1 ml/kg and 36.0 ml/kg in both groups, respectively (p = 0.630). ∆RBV correlated inversely with Vs (rs = -0.299, p = 0.008). DISCUSSION The present study suggests that patients with higher BMI and lower Vs experience larger blood volume changes, despite similar ultrafiltration requirements. These results underline the clinical plausibility and importance of dialysate bolus-based absolute blood volume determination in the assessment of target weight, especially in view of a previous study where intradialytic morbid events could be decreased when the target weight was adjusted, based on Vs.
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Affiliation(s)
- Michael Schmiedecker
- Department of Medicine III, Division of Nephrology & Dialysis, Medical University of Vienna, Vienna, Austria
| | - Simon Krenn
- Department of Medicine III, Division of Nephrology & Dialysis, Medical University of Vienna, Vienna, Austria.,Center for Public Health, Department of Epidemiology, Medical University of Vienna, Vienna, Austria.,AIT Austrian Institute of Technology, Center for Health & Bioresources, Medical Signal Analysis, Vienna, Austria
| | - Maximilian Waller
- Department of Medicine III, Division of Nephrology & Dialysis, Medical University of Vienna, Vienna, Austria.,Department of Nephrology, Klinik Favoriten Vienna, Vienna, Austria
| | - Christopher Paschen
- Department of Medicine III, Division of Nephrology & Dialysis, Medical University of Vienna, Vienna, Austria
| | - Sebastian Mussnig
- Department of Medicine III, Division of Nephrology & Dialysis, Medical University of Vienna, Vienna, Austria
| | - Janosch Niknam
- Department of Medicine III, Division of Nephrology & Dialysis, Medical University of Vienna, Vienna, Austria
| | | | - Christopher C Mayer
- AIT Austrian Institute of Technology, Center for Health & Bioresources, Medical Signal Analysis, Vienna, Austria
| | - Manfred Hecking
- Department of Medicine III, Division of Nephrology & Dialysis, Medical University of Vienna, Vienna, Austria
| | - Daniel Schneditz
- Otto Loewi Research Center, Division of Physiology, Medical University of Graz, Graz, Austria
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Raimann JG, Wang Y, Mermelstein A, Kotanko P, Daugirdas JT. Ultrafiltration rate thresholds associated with increased mortality risk in hemodialysis, unscaled or scaled to body size. Kidney Int Rep 2022; 7:1585-1593. [PMID: 35812299 PMCID: PMC9263411 DOI: 10.1016/j.ekir.2022.04.079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 11/29/2022] Open
Abstract
Introduction One proposed threshold ultrafiltration rate (UFR) of concern in hemodialysis patients is 13 ml/h per kg. We evaluated associations among UFR, postdialysis weight, and mortality to determine whether exceeding such a threshold would result in similar levels of risk for patients of different body weights. Methods Data were analyzed in this retrospective cohort study for 1 year following dialysis initiation (baseline) and over 2 years of follow-up in incident patients receiving thrice-weekly in-center hemodialysis. Patient-level UFR was averaged over the baseline period. To investigate the joint effect of UFR and postdialysis weight on survival, we fit Cox proportional hazards models using bivariate tensor product spline functions, adjusting for sex, race, age, diabetes, and predialysis serum albumin, phosphorus, and systolic blood pressure (BP). We constructed contour plots of mortality hazard ratios (MHRs) over the entire range of UFR values and postdialysis weights. Results In the studied 2542 patients, UFR not scaled to body weight was strongly associated with MHR, whereas postdialysis weight was inversely associated with MHR. MHR crossed 1.5 when unscaled UFR exceeded 1000 ml/h, and this relationship was largely independent of postdialysis weight in the range of 80 to 140 kg. A UFR warning level associated with a lower MHR of 1.3 would be 900 ml/h, whereas the UFR associated with an MHR of 1.0 was patient-size dependent. The MHR when exceeding a UFR threshold of 13 ml/h per kg was dependent on patient weight (MHR = 1.20, 1.45, and >2.0 for a 60, 80, and 100 kg patient, respectively). Conclusion UFR thresholds based on unscaled UFR give more uniform risk levels for patients of different sizes than thresholds based on UFR/kg.
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