Effect of Viscous Fiber on Postprandial Kalemic Response in Hemodialysis Patients

High blood potassium levels (hyperkalemia) is a major problem for people with kidney failure undergoing hemodialysis treatment. In order to reduce the risk of hyperkalemia, people with kidney failure are advised to limit or avoid high-potassium foods. However, high-potassium foods comprise many healthy food choices, including commonly consumed fruits and vegetables that are key sources of dietary fiber, and other important nutrients.

Risk of hyperkalemia from dietary potassium intake is most notable in the first few hours after a meal when ingested potassium enters the bloodstream. In general, dietary potassium is very well absorbed. However, dietary fiber has been shown to increase the proportion of dietary potassium that is excreted in stool. Based on these findings, it has been proposed that fiber may help to lower the risk of hyperkalemia in people with kidney disease. It remains unclear whether dietary fiber increases potassium excretion in stool by reducing the absorption of dietary potassium, or by drawing body potassium into the bowels by increasing stool bulk. The distinction may be important, as reducing potassium absorption would be expected to be of greater benefit in preventing hyperkalemia caused by eating high-potassium foods.

In this study, the investigators will assess whether a fiber supplement can reduce the effect of dietary potassium from orange juice on blood potassium levels in people with kidney disease undergoing maintenance hemodialysis treatment.

Study Overview

• Status: Enrolling by invitation
• Conditions: Hyperkalemia; Chronic Kidney Disease Requiring Chronic Dialysis
• Intervention / Treatment: Diagnostic test: Kalemic Response to Orange Juice; Dietary supplement: Kalemic Response to Orange Juice with Fiber

Detailed Description

The source population for this study will be adults (18-89 years old) with kidney failure undergoing thrice weekly maintenance hemodialysis (HD) treatment. Participants will include 10 patients without diabetes mellitus, and 10 patients with type 2 diabetes mellitus (T2D) that is being managed with lifestyle with or without long-acting insulin. Patients with a moderate hyperkalemia (>6.5 mEq/L) in the last 6-months, taking potassium-lowering medications, having gastrointestinal (GI) disorders that may alter potassium digestion and absorption, and low hemoglobin concentrations (<10.0 g/dL) will be excluded. In addition, participants who are deemed inappropriate for the intervention by the study Nephrologist based on cognition, prognosis or pending treatments will be excluded.

Once enrolled, participants will be asked to complete questionnaires on demographics, dietary intake, GI symptoms, and urine output. In addition, baseline data on anthropometrics, physical function, medical history and blood parameters will be obtained by physical exam and review of medical records.

Treatment measurement visits will be conducted on the same non-dialysis treatment days at the University of Nevada, Reno Clinical Research Center with participants in a fasted state. Serial blood samples will be collected before, and 60, 120 and 180 minutes after ingesting orange juice providing 0.35 mEq/kg dose of potassium alone, or with 0.15 g/kg of psyllium-based fiber. The sequence of treatments (1) orange juice or 2) orange juice + fiber) will be randomly assigned with equal allocation by T2D status. If a participant's body weight exceeds 120% of ideal body weight (IBW), then the dose of orange juice and fiber will be based on adjusted body weight.

Blood tests at times 0 and 60-minutes post-treatment will be analyzed for the basic metabolic panel plus insulin, and the 120- and 180-minutes blood samples will be analyzed for potassium concentrations. The kalemic response to study treatments will assessed based on: 1) peak change in plasma potassium concentrations, and 2) total area under the curve for plasma potassium until 180-minutes. These parameters will be compared across treatment conditions using paired t-test. If non-normally distributed, values will be log-transformed prior to analyses.

• Study Type: Observational
• Enrollment (Anticipated): 20

Contacts and Locations

Study Locations

• United States
  • Nevada
    • Reno, Nevada, United States, 89557
      • University of Nevada,Reno

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 89 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

The source population for this intervention will be adults (18-89 years) with kidney failure undergoing thrice-weekly maintenance hemodialysis treatment

Description

Inclusion Criteria:

• Kidney failure undergoing thrice-weekly maintenance hemodialysis
• 10 patients without diabetes mellitus, and 10 patients with type 2 diabetes mellitus (T2D) that are being managed with lifestyle and/or long-acting insulin

Exclusion Criteria:

• Moderate hyperkalemia (>6.5 mEq/L) in the last 6-months.
• Potassium-lowering medications
• Gastrointestinal (GI) diseases that may alter potassium digestion and absorption.
• Low hemoglobin concentrations (<10.0 g/dL).
• Deemed to be inappropriate for the intervention by Study Nephrologist based on cognition, prognosis, or pending treatments
• Women who are pregnant or who plan to become pregnant

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Orange Juice (control); Orange juice providing a 0.35 mEq/kg dose of potassium	Diagnostic test: Kalemic Response to Orange Juice; 100% pulp-free orange juice
Orange Juice plus Fiber; Same amount of orange juice as Orange Juice treatment with 0.15 g/kg of psyllium-based fiber added	Dietary supplement: Kalemic Response to Orange Juice with Fiber; 100% pulp-free orange juice with psyllium-based fiber added

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak change in plasma potassium levels	The kalemic response to study treatments will be assessed based on peak change in plasma potassium concentrations compared to pre-treatment.	0 to 180-minutes
Plasma potassium area under the curve	The kalemic response to study treatments will be assessed based on total area under the curve for plasma potassium concentrations from pre-treatment to 180-minutes.	0 to 180-minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak change in plasma potassium levels by diabetes status	The kalemic response to study treatments (Primary Outcome 1) will be compared between participants with and without type 2 diabetes mellitus.	0 to 180-minutes
Plasma potassium area under the curve by diabetes status	The kalemic response to study treatments (Primary Outcome 2) will be compared between participants with and without type 2 diabetes mellitus.	0 to 180-minutes

Collaborators and Investigators

• Sponsor: University of Nevada, Reno
• Collaborators: United States Department of Agriculture (USDA); Sierra Nevada Nephrology Consultants, Inc.
• Investigators: Principal Investigator: David E St-jules, PhD, University of Nevada, Reno

Publications and helpful links

General Publications

• St-Jules DE, Goldfarb DS, Sevick MA. Nutrient Non-equivalence: Does Restricting High-Potassium Plant Foods Help to Prevent Hyperkalemia in Hemodialysis Patients? J Ren Nutr. 2016 Sep;26(5):282-7. doi: 10.1053/j.jrn.2016.02.005. Epub 2016 Mar 12. Erratum In: J Ren Nutr. 2016 Nov;26(6):416.
• Cummings JH, Hill MJ, Jenkins DJ, Pearson JR, Wiggins HS. Changes in fecal composition and colonic function due to cereal fiber. Am J Clin Nutr. 1976 Dec;29(12):1468-73. doi: 10.1093/ajcn/29.12.1468.
• Allon M, Dansby L, Shanklin N. Glucose modulation of the disposal of an acute potassium load in patients with end-stage renal disease. Am J Med. 1993 May;94(5):475-482. doi: 10.1016/0002-9343(93)90081-Y.

Study record dates

Study Major Dates

• Study Start (ACTUAL): June 29, 2021
• Primary Completion (ANTICIPATED): January 31, 2022
• Study Completion (ANTICIPATED): June 30, 2022

Study Registration Dates

• First Submitted: July 12, 2021
• First Submitted That Met QC Criteria: October 6, 2021
• First Posted (ACTUAL): October 20, 2021

Study Record Updates

• Last Update Posted (ACTUAL): October 20, 2021
• Last Update Submitted That Met QC Criteria: October 6, 2021
• Last Verified: October 1, 2021

More Information

Terms related to this study

• Keywords: Chronic kidney disease; Hemodialysis; Hyperkalemia; Dietary fiber
• Additional Relevant MeSH Terms: Metabolic Diseases; Urologic Diseases; Renal Insufficiency; Water-Electrolyte Imbalance; Kidney Diseases; Renal Insufficiency, Chronic; Hyperkalemia
• Other Study ID Numbers: 1596754

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The IPD will be available after being unidentified to those who will contact the principal investigator for research purposes.
• IPD Sharing Time Frame: After publishing the primary and secondary outcome paper.
• IPD Sharing Access Criteria: Anyone who is interested to do secondary analysis.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No