Observational Single-center Study of the Relationship Between Arterial Hypertension and Hypervolemia Defined by Self-measurement of Impedancemetry in Kidney Transplant Patients With Transplantation Less Than 6 Months Old (HTAôConnect)

Monocentric Observational Study to Determine the Relationship Between Arterial Hypertension and Hypervolaemia, Defined by Self-measurement of Impedancemetry in Kidney Transplant Recipients Under 6 Months Old

The working hypothesis is that hypertension during the first post-transplant trimester is partly explained by the patient's hypervolemia. The main objective of the single-center observational study "HTA ô Connect" is to study the relationship between hypertension and extracellular hyperhydration, thanks to repeated self-measurements of blood pressure and impedancemetry between the 30th and the 90th day post-transplant, in 150 incident kidney transplant patients from our department, the ITUN (Institute of Urology-Nephrology Transplantation).

The study population involves 150 incident kidney transplant patients, presenting to the Nantes University Hospital Transplant Institute for 1 month (D30), and presenting with hypertension ≥ 140/90mmHg and not treated with a diuretic.

Data collected at the patients' homes will be used to establish a relationship between blood pressure and extracellular water volume. The data collected will not be used to follow up patients who participated in the study in this first stage of exploration.

Study Overview

• Status: Completed
• Conditions: Kidney Transplant Patients
• Intervention / Treatment: Other: Measurement of systolic and diastolic blood pressure, impedancemetry, weight, creatinemia and Pro-BNP measurements

Detailed Description

Evaluation parameters

1. Blood pressure :

   • At inclusion and at the end of the study (in consultation at D30 and D90, respectively), blood pressure will be measured 3 times after a few minutes of rest in a sitting position Hypertension in consultation will be defined by values > 140/90 mmHg.
   • Between D30 and D90, blood pressure will be measured by self-measurement using DM-certified devices, 3 times in the morning at breakfast and in the evening before bedtime, in a sitting position after a few minutes of rest. The operation will be repeated 3 days a week (Monday to Wednesday) between the 30th and the 90th day post-transplant. Self-measurement hypertension will be defined by values > 135/85 mmHg. Self-measurement blood pressure data will be directly transmitted to the "INTEGRALIS" specialty medical record of transplant patients at the ITUN via the epatient application (https://www.idbc.fr/e-patient/).

2. Weight :

   • Weight will be measured only once at the inclusion consultation (D30) and at the end of the study (D90).
   • Between D30 and D90 the weight will be measured by self-measurement using DM certified scales. The operation will be repeated once in the morning and once in the evening at the time of blood pressure measurements, 3 days a week (Monday to Wednesday) between the 30th and the 90th day after transplantation. The data from the self-measurement of weight will be directly transmitted to the "INTEGRALIS" medical record of the transplanted patients at the ITUN

3. Impedance measurement :

   • At inclusion and at the end of the study in consultation, respectively at D 30 and D90, impedancemetry will be measured once
   • Between D30 and D90, impedancemetry measurements will be collected at the same time as blood pressure measurements at the patients' homes by self-measurement 3 times in the morning and 3 times in the evening, 3 days a week (from Monday to Wednesday) between the 30th and the 90th day after transplantation. The impedancemetry will be collected with the help of a bluetooth-connected BIODYLIFEZM self-measurement device. The impedancemetry data collected via bluetooth will be directly transmitted to the "INTEGRALIS" specialty medical record of the transplanted patients at the ITUN.

• Study Type: Observational
• Enrollment (Actual): 57

Contacts and Locations

Study Locations

• France
  • Loire-Atlantique
    • Nantes, Loire-Atlantique, France, 44093
      • Nantes University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population involves 150 incident kidney transplant patients, presenting to the Nantes University Hospital Transplant Institute for 1 month (D30), and presenting with hypertension ≥ 140/90mmHg recorded in the outpatient clinic at the Nantes University Hospital, according to the recommendations of the French Society of Arterial Hypertension (6) and not treated with a diuretic.

There will be no emergency inclusion. Recently transplanted patients will come regularly, between 1 and 2 times per week, to the Nantes University Hospital during the first month. The study will be presented to them during this period and they will be included at the D30 (M1) consultation.

Description

Inclusion Criteria :

• Age ≥ 18 years
• Blood pressure ≥ 140/90mmHg on 3 occasions and according to the recommendations of the French Society of Hypertension (6) at the M1 consultation
• Patients 1 to 6 months post-kidney transplant
• Isolated kidney transplant patient
• BMI between 16 and 34 kg/cm2
• Not opposed to the research

Exclusion Criteria :

• History of non-renal transplantation
• Patients treated with diuretics on the day of inclusion
• Minors, adults under guardianship and protected persons

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between Hypertension and extracellular hyperhydration	Hypertension will be assessed by measurement of blood pressure	Day 90
Correlation between Hypertension and extracellular hyperhydration	Extracellular hyperhydration will be measured by impedance measurement	Day 90

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
hypertension measurement	Blood pressure : At inclusion and at the end of the study (in consultation at Day 30 and Day 90, respectively), blood pressure will be measured 3 times after a few minutes of rest in a sitting position Hypertension in consultation will be defined by values > 140/90 mmHg. • Between Day 30 and D90, blood pressure will be measured by self-measurement using DM-certified devices, 3 times in the morning at breakfast and in the evening before bedtime, in a sitting position after a few minutes of rest. The operation will be repeated 3 days a week (Monday to Wednesday) between the 30th and the 90th day post-transplant. Self-measurement hypertension will be defined by values > 135/85 mmHg.	For 3 month post-transplant
Impedance measurement	At inclusion and at the end of the study in consultation, respectively at Day 30 and D90, impedancemetry will be measured once. • Between Day 30 and Day 90, impedancemetry measurements will be collected at the same time as blood pressure measurements at the patients' homes by self-measurement 3 times in the morning and 3 times in the evening, 3 days a week (from Monday to Wednesday) between the 30th and the 90th day after transplantation.	For 3 month post-transplant
Weight measurement	Weight will be measured only once at the inclusion consultation	day 30
Weight measurement	Weight will be measured at the end of the study .	Day 90
Weight measurement	The weight will be measured by self-measurement using DM certified scales.	3 days a week between the 30th and the 90th day after transplantation.
Correlation between repeated systolic and diastolic blood pressure self-measurements and patient weight	blood pressure will be measured 3 times after a few minutes of rest in a sitting position Hypertension in consultation will be defined by values > 140/90 mmHg.; Between Day 30 and D90, blood pressure will be measured by self-measurement using DM-certified devices, 3 times a week.; Weight will be measured only once at the inclusion consultation (Day30) and at the end of the study (Day 90).; Between Day30 and Day 90 the weight will be measured by self-measurement using DM certified scales.	Day 90
Correlation between repeated self-measurements of extracellular hyperhydration	Impedance measurement	3 times a week
Correlation between repeated self-measurements of extracellular hyperhydration	Weight	3 times a week
Correlation between repeated self-measurement of systolic and diastolic blood pressure and creatinemia and pro-BNP blood	Composites criteria : Systolic and diastolic blood pressure will be assessed by measurement of blood pressure Plasma creatinine and proBNP will mesuread by a blood test	Day 90
Correlation between repeated self-measurement of extracellular hyperhydration indices by impedancemetry and creatinemia and pro-BNP blood	Composites criteria : Extracellular hyperhydration will be measured by impedance measurement Plasma creatinine and proBNP will mesuread by a blood test	Day 90

Collaborators and Investigators

• Sponsor: Nantes University Hospital
• Investigators: Principal Investigator: Claire GARANDEAU, PH, Nantes University Hospital

Study record dates

Study Major Dates

• Study Start (Actual): October 14, 2021
• Primary Completion (Actual): March 17, 2026
• Study Completion (Actual): March 17, 2026

Study Registration Dates

• First Submitted: June 8, 2021
• First Submitted That Met QC Criteria: August 31, 2021
• First Posted (Actual): September 10, 2021

Study Record Updates

• Last Update Posted (Actual): May 13, 2026
• Last Update Submitted That Met QC Criteria: May 12, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Hypertension; Hypervolemia; Self-measurement; Connected
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hypertension; Edema; Investigative Techniques; Diagnostic Techniques and Procedures; Diagnosis; Circulatory and Respiratory Physiological Phenomena; Physical Examination; Vital Signs; Hemodynamics; Cardiovascular Physiological Phenomena; Weights and Measures; Blood Pressure
• Other Study ID Numbers: RC20_0484

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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