Measurement of Sweat Sodium Concentration in Patients With Chronic Kidney Disease

Application of Pilocarpine Iontophoresis in Patients With Chronic Kidney Disease: a Feasibility Study

It has been shown that excretion of sodium and water through the skin in the form of sweat represents a regulatory mechanism of electrolyte- and fluid balance. Since patients with chronic kidney disease (CKD) exhibit increased skin sodium content, we investigated the feasibility of sweat testing as a novel experimental tool to a more complete assessment of fluid- and sodium homeostasis.

In this cross-sectional feasibility study, we applied pilocarpine iontophoresis to induce sweat testing in 58 patients across various stages of CKD including patients after kidney transplantation as well as a healthy control cohort (n=6) to investigate possible effects of CKD and transplantation status on sweat rate and sodium concentration. Due to non-linear relationships, we modeled our data using polynomial regression.

Decline of kidney function showed a significant association with lower sweat rates: adj R²= 0.2278, F(2, 61) = 10.29, p = 0.000141. Sweat sodium concentrations were increased in moderate CKD, however this effect was lost in end stage renal disease: adj R² = 0.3701, F(4, 59) = 10.26, p = 2.261e-06. We observed higher sweat weight in males compared to females.

Diagnostic sweat analysis represents an innovative and promising noninvasive option for more thorough investigation of sodium- and fluid homeostasis in CKD patients. Lower sweat rates and higher sweat sodium concentrations represent a unique feature of CKD patients with potential therapeutic implications.

Study Overview

• Status: Completed
• Conditions: Chronic Kidney Diseases
• Intervention / Treatment: Diagnostic test: pilocarpine iontopheresis

• Study Type: Observational
• Enrollment (Actual): 64

Contacts and Locations

Study Locations

• Austria
  • Vienna, Austria, 1090
    • Medical University of Vienna

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Healthy controls older than 18 years old. Patients older than 18 years old with all grades of Chronic Kidney Disease (also patients receiving hemodialysis)

Description

Inclusion Criteria:

Completed 18th year of life and the ability and willingness to provide informed consent

Exclusion Criteria:

General exclusion criteria were signs of acute infection, clinical signs of kidney graft rejection or pregnancy. Exclusion criteria for the healthy controls were pregnancy or the presence of chronic metabolic, renal, cardiovascular, or rheumatologic conditions, hypertension, chronic or recent intake (8 weeks prior to testing) of psychiatric or antihypertensive medication.

Study Plan

How is the study designed?

Number of groups / cohorts

8

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Control; Healthy control subjects	Diagnostic test: pilocarpine iontopheresis; Application of pilocarpine on the skin of the patients/subjects to induce sweat production to analyse sweat sodium concentration via flame photometry
CKDI; Patients with chronic kidney disease G1	Diagnostic test: pilocarpine iontopheresis; Application of pilocarpine on the skin of the patients/subjects to induce sweat production to analyse sweat sodium concentration via flame photometry
CKDII; Patients with chronic kidney disease G2	Diagnostic test: pilocarpine iontopheresis; Application of pilocarpine on the skin of the patients/subjects to induce sweat production to analyse sweat sodium concentration via flame photometry
CKDIIIa; Patients with chronic kidney disease G3a	Diagnostic test: pilocarpine iontopheresis; Application of pilocarpine on the skin of the patients/subjects to induce sweat production to analyse sweat sodium concentration via flame photometry
CKDIIIb; Patients with chronic kidney disease G3b	Diagnostic test: pilocarpine iontopheresis; Application of pilocarpine on the skin of the patients/subjects to induce sweat production to analyse sweat sodium concentration via flame photometry
CKDIV; Patients with chronic kidney disease G4	Diagnostic test: pilocarpine iontopheresis; Application of pilocarpine on the skin of the patients/subjects to induce sweat production to analyse sweat sodium concentration via flame photometry
CKDV; Patients with chronic kidney disease G5	Diagnostic test: pilocarpine iontopheresis; Application of pilocarpine on the skin of the patients/subjects to induce sweat production to analyse sweat sodium concentration via flame photometry
CKDVd; Patients with chronic kidney disease G5 receiving hemodialysis	Diagnostic test: pilocarpine iontopheresis; Application of pilocarpine on the skin of the patients/subjects to induce sweat production to analyse sweat sodium concentration via flame photometry

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sweat sodium concentration	Sodium concentration of induced sweat by pilocarpine iontopheresis in mmol/L	Right after study inclusion of patients/subjects

Collaborators and Investigators

• Sponsor: Medical University of Vienna
• Investigators: Principal Investigator: Johannes Kovarik, MD, PhD, Medical University of Vienna

Study record dates

Study Major Dates

• Study Start (Actual): October 5, 2018
• Primary Completion (Actual): December 11, 2020
• Study Completion (Actual): December 11, 2020

Study Registration Dates

• First Submitted: April 3, 2024
• First Submitted That Met QC Criteria: April 3, 2024
• First Posted (Actual): April 9, 2024

Study Record Updates

• Last Update Posted (Actual): April 9, 2024
• Last Update Submitted That Met QC Criteria: April 3, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Urologic Diseases; Disease Attributes; Renal Insufficiency; Chronic Disease; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Kidney Diseases; Renal Insufficiency, Chronic; Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Autonomic Agents; Peripheral Nervous System Agents; Cholinergic Agents; Cholinergic Agonists; Miotics; Muscarinic Agonists; Pilocarpine
• Other Study ID Numbers: 12345678

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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