Continuous Glucose Monitoring (CGM) After Kidney Transplantation (CGM-KTx)

Continuous Glucose Monitoring in Kidney Transplant Recipients with Diabetes, Pre-diabetes and Without Diabetes

This study examines glucose levels measured by continuous glucose monitoring (CGM) in the immediate period following kidney transplantation among recipients with diabetes, without diabetes, and with pre-diabetes.

The primary objective is to analyse differences in mean sensor glucose between these three groups.

CGMs are applied to participants within 72 hours after kidney transplantation, with a total of 54 participants divided equally across the three groups (18 in each).

Secondary objectives include assessing additional glucose profile indices, adherence to relevant guidelines, changes in HbA1c, the impact of immunosuppression and steroid dosage, and beta cell function.

Study Overview

• Status: Recruiting
• Conditions: Kidney Transplantation; Hyperglycaemia

Detailed Description

Introduction:

Hyperglycaemia is a common medical complication within the first two weeks following kidney transplantation. High doses of prednisone induce a state of insulin resistance, which can cause hyperglycaemia or disrupt glucose regulation in patients with pre-existing diabetes. Current guidelines recommend daily blood glucose monitoring (BGM), defined as four daily glucose measurements during the first four days post-transplant, with insulin administered to maintain stable glucose levels. Minor studies using continuous glucose monitoring (CGM) suggest that patients, particularly those with diabetes, are prone to dysregulation. Early and optimised treatment of post-surgical hyperglycaemia may reduce the risk of later post-transplant diabetes mellitus (PTDM) and associated cardiovascular mortality and loss of graft function.

Objectives:

This study aims to investigate differences in glucose profiles during the initial two weeks following kidney transplantation among patients with diabetes, prediabetes, and no diabetes. We hypothesise that patients with pre-existing diabetes will exhibit the highest glucose levels, despite insulin treatment.

Background:

Patients with end-stage kidney disease require kidney replacement therapy, provided through haemodialysis, peritoneal dialysis, or kidney transplantation. Kidney transplantation is generally considered the best option in terms of quality of life and cost-effectiveness. However, kidney transplant recipients require complex immunosuppressive regimens and present an increased susceptibility to infection, malignancy, cardiovascular disease, and diabetes risk.

Post-transplant hyperglycaemia frequently develops in the early weeks after kidney transplantation. This condition resembles type 2 diabetes and necessitates glucose-lowering therapy to mitigate its harmful effects. Hyperglycaemia primarily arises due to high-dose glucocorticoids or surgical stress, both of which induce insulin resistance. It is characterised by a plasma glucose level of ≥7.0 mmol/L or a 2-hour plasma glucose level of ≥11.1 mmol/L after an oral glucose tolerance test.

Early post-transplant hyperglycaemia exerts stress on pancreatic beta cells, which may contribute to the development of PTDM later on. Although hyperglycaemia may resolve with reduced doses of glucocorticoids and calcineurin inhibitors, kidney transplant recipients remain at an increased risk of PTDM, with an estimated one-year risk of 10-15%. PTDM can be diagnosed three months post-transplant, once patients are on stable immunosuppressive therapy and exhibit stable kidney graft function. Insulin resistance and steroid-induced weight gain play a significant role in the development of PTDM, with hyperglycaemia from steroids often presenting as elevated postprandial glucose levels. Glucose measurement 7-8 hours after prednisolone administration may be optimal for detecting hyperglycaemia, but an oral glucose tolerance test is considered even more effective.

Identifying post-transplant hyperglycaemia early is critical for reducing the risk of developing PTDM. Long-term, PTDM is associated with an increased risk of cardiovascular mortality and reduced graft survival.

Continuous glucose monitoring (CGM) are gradually becoming more widely used for glucose monitoring in patients with impaired glucose levels. Plasma glucose is measured every 5-15 minutes, depending on the model used, usually for 10-14 days. A sensor measures interstitial glucose, which is converted to plasma glucose levels. This provides precise measurements of plasma glucose, including during sleep and periods of variability. This enables clinicians to optimise treatment based on comprehensive glycaemic profiles.

Other metrics, such as time in range and glucose management indicator (GMI) - a calculated estimation of HbA1c based on mean glucose - are also provided by the CGM.

Few studies have explored glucose profiles by CGM immediately after kidney transplantation. A small study found a significant association between mean sensor glucose 3-5 days after renal transplantation and later development of PTDM. Data was based on glucose profiles measured by CGM on 28 kidney transplanted patients and glucose profiles also revealed higher glucose levels in the afternoon and early evening.

Design and Population:

This single-centre observational study will be conducted at Rigshospitalet in Copenhagen, Denmark. A total of 54 participants will be included, divided into three groups based on their diabetes status or most recent fasting plasma glucose and HbA1c measurements before transplantation:

• Diabetes group (n=18)
• No diabetes group (n=18)
• Prediabetes group (n=18)

Methods:

Kidney transplant recipients will receive information about the study prior to or upon admission before transplantation. Patients who meet the inclusion and exclusion criteria and provide written, informed consent will be enrolled in one of the three groups.

A CGM will be applied within 72 hours of kidney transplantation, and additional blood samples (HbA1c, C-peptide, and insulin) will be taken. The CGM will measure glucose levels for 10-14 days, depending on the model used, and additional blood samples will be collected upon CGM removal. Data during the CGM monitoring period, including medication, complications, blood samples, and vital signs, will be obtained from patients' records. Since the CGMs are double-blinded, treating physicians will adhere to guidelines for managing hyperglycaemia.

Statistical Analysis:

We will compare the mean sensor glucose levels across the three groups using analysis of variance (ANOVA) or the Kruskal-Wallis test, depending on data distribution. Post-hoc tests will identify specific group differences in glucose levels. Regression analyses, such as logistic and linear regression, will examine associations between the groups on secondary outcomes, and multivariate analysis will be conducted.

Ethical Considerations:

This study aims to contribute to understanding glucose profiles post-kidney transplantation, ultimately improving monitoring and treatment for post-transplant hyperglycaemia. Informed consent is essential to ensure participants understand the study's purpose and procedures. Special considerations will be taken to protect the autonomy and well-being of kidney transplant recipients, a potentially vulnerable population

• Study Type: Observational
• Enrollment (Estimated): 54

Contacts and Locations

• Study Contact: Name: Ida S Voss, MD; Phone Number: +4535457063; Email: ida.voss@regionh.dk

Study Locations

• Denmark
  • DK
    • Copenhagen, DK, Denmark, 2100
      • Recruiting
      • Rigshospitalet
      • Contact: Tobias Bomholt, MD, PhD; Phone Number: +4535457952; Email: Tobias.bomholt@regionh.dk
      • Contact: Ida S Voss, MD; Phone Number: +4535457063; Email: ida.voss@regionh.dk
      • Contact: Ida S Voss, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult kidney transplant recipients at Rigshospitalet, Copenhagen, Denmark

Description

Inclusion Criteria:

• Written informed consent obtained before CGM application
• Male or female; age: ≥18 years
• Kidney transplantation

Exclusion Criteria:

• Unable to cooperate to CGM the first ten days after surgery
• Allergic to plasters in CGM units
• Combined kidney and liver or pancreatic transplantation
• Graft loss/rejection within first 48 hours after transplantation

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Diabetes; Diabetes group defined as type 2 diabetes, type 1 diabetes, receiving glucose-lowering therapy, FPG ≥ 7 mmol/l, HbA1c ≥ 48mmol/l or non-fasting plasma glucose ≥11.1 mmol/l
No diabetes; No diabetes defined as HbA1c <42mmol/mol or FPG<6.1 mmol/L
Prediabetes; Prediabetes group defined as HbA1c 42-47 mmol/mol or FPG 6.1-6.9 mmol/L

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in Mean Sensor Glucose	Mean sensor glucose (mmol/L) evaluated by CGM	10 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time in range (%)	Time within 3.9-10.0 mmol/L as evaluated by CGM	10 days
Compliance with applicable guideline (%)	Based on capillary blood glucose (mmol/L) and daily insulin dose (IE per day)	10 days
Time in hypoglycaemia (%)	Time in level 1 (3.0-3.8 mmol/L) and level 2 (below 3.0 mmol/L]) evaluated by CGM	10 days
Time in tight glycaemic range (%)	Time in 3.9-7.8 mmol/L evaluated by CGM	10 days
Time i hyperglycaemia (%)	Time in level 1 (10.1-13.9 mmol/L) and level 2 (above 13.9 mmol/L) evaluated by CGM	10 days
Glucose variability	Standard deviation [mmol/L] and coefficient of variation [%]) evaluated by CGM	10 days
Glucose management indicator (GMI) (mmol/mol and %)	Evaluated by CGM	10 days
Number of hyperglycaemic events (Number/days measured)	Defined as glucose ≥10.0mmol/L for more than 15 minutes measured by CGM	10 days
Number of hypoglycaemic events (Number/days measured)	Defined as glucose <3.9mmol/L for more than 15 minutes measured by CGM	10 days

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
HbA1c	Changes in HbA1c (mmol/mol and %) 10-14 days after kidney transplantation	10 days
Daily dose of immunosuppressant	prednisone, tacrolimus, cyclosporine, mycophenolate mofetil	10 days
HOMA	HOMA calculated from fasting glucose (mmol/L) and fasting plasma insulin (pmol/L) at time of transplantation and 10-14 days after kidney transplantation	10 days

Collaborators and Investigators

• Sponsor: Bo Feldt-Rasmussen

Study record dates

Study Major Dates

• Study Start (Actual): November 12, 2024
• Primary Completion (Estimated): January 1, 2026
• Study Completion (Estimated): January 1, 2026

Study Registration Dates

• First Submitted: October 31, 2024
• First Submitted That Met QC Criteria: November 4, 2024
• First Posted (Actual): November 5, 2024

Study Record Updates

• Last Update Posted (Estimated): November 13, 2024
• Last Update Submitted That Met QC Criteria: November 12, 2024
• Last Verified: November 1, 2024

More Information

Terms related to this study

• Keywords: diabetes; CGM; Kidney transplantation; prediabetes; continuous glucose monitoring; hyperglycaemia
• Additional Relevant MeSH Terms: Metabolic Diseases; Glucose Metabolism Disorders; Hyperglycemia
• Other Study ID Numbers: H-24046404

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
• product manufactured in and exported from the U.S.: No