The Link Between Time In Range Versus HbA1c and the Presence of Chronic COmplications in Type 1 Diabetes: a Longitudinal Study

Study Overview
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Brief Summary
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HbA1c is currently the only metric of glucose control showing an association with chronic complications of type 1 diabetes mellitus (T1D). Time in range (TIR, 70-180 mg/dL) measured by real-time continuous glucose monitoring (CGM) might be a better marker. In this study, the investigators studied the clinical significance of a 10% increase of TIR over two years.

Detailed Description
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Adult subjects (age ≥ 18 years) with T1D were consecutively recruited in three multicenter studies (RESCUE, FUTURE, ALERTT1 studies) organized between September 2014 and 19 November 2021. For the TIRCO study, only the data from patients recruited at the University Hospital of Antwerp were analyzed. Initially, the data from 498 patients were collected. Pregnant patients and patients with beta-cell transplantation were excluded from the study, resulting in the inclusion of 479 patients. Consecutive patients starting CGM were proposed to participate and were included into the study after signing informed consent. The study population consisted of 445 patients who used Freestyle libre, 21 patients who used CGM in hybrid closed loop and 13 patients who used Dexcom G4 and G6, resulting in a total of 479 patients. In this project, the investigators looked into the link between TIR versus HbA1c and the presence of chronic complications in adults with T1D. The primary endpoint was to evaluate the link between TIR and the presence of chronic microvascular complications as formulated by the following research question: What is the clinical significance of a 10% increase of TIR over two years? The secondary endpoint was to assess the link between TIR and independent risk factors for micro- and macrovascular complications such as sex, age, BMI, lipids, blood pressure, HbA1c, time in range, mean glucose, diabetes duration, method of insulin administration (MDI or CSII), type of sensor and sensor compliance.

Official Title
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The Link Between Time In Range Versus HbA1c and the Presence of Chronic COmplications in Type 1 Diabetes: a Longitudinal Study - The TIRCO Study

Conditions
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Diabetes Mellitus, Type 1

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Type 1 diabetes mellitus Using Real-Time Continuous Glucose Monitoring (rtCGM), Intermittently Scanned CGM (isCGM) or (Hybrid) Closed Loop (HCL) as diabetes treatment Willing to sign informed consent Exclusion Criteria: Pregnancy Patients that had beta-cell transplantation

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time In Range (TIR, 70-180 mg/dL) | Change in time spent in range (70-180 mg/dL) from baseline to 12 months | 12 months | 
| Time In Range (TIR, 70-180 mg/dL) | Change in time spent in range (70-180 mg/dL) from baseline to 24 months; Change of 10% in time spent in range (70-180 mg/dL) compared from baseline to 24 months | 24 months | 
| Diabetic eye disease | Change in presence of microvascular complication 'Diabetic eye disease' (preproliferative retinopathy, proliferative retinopathy, maculopathy) from baseline to 12 months | 12 months | 
| Diabetic eye disease | Change in presence of microvascular complication 'Diabetic eye disease' (preproliferative retinopathy, proliferative retinopathy, maculopathy) from baseline to 24 months | 24 months | 
| Nephropathy | Change in presence of microvascular complication 'Nephropathy' (albuminuria ≥ 20µg/min or eGFR < 60 ml/min/1,73m^2) from baseline to 12 months | 12 months | 
| Nephropathy | Change in presence of microvascular complication 'Nephropathy' (albuminuria ≥ 20µg/min or eGFR < 60 ml/min/1,73m^2) from baseline to 24 months | 24 months | 
| Neuropathy | Change in presence of microvascular complication 'Neuropathy' (monofilament score < 12/12) from baseline to 12 months | 12 months | 
| Neuropathy | Change in presence of microvascular complication 'Neuropathy' (monofilament score < 12/12) from baseline to 24 months | 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| HbA1c (%) | Change in HbA1c from baseline to 12 months | 12 months | 
| HbA1c (%) | Change in HbA1c from baseline to 24 months | 24 months | 
| Mean glucose (mg/dl) | Change in mean glucose (mg/dl) from baseline to 12 months | 12 months | 
| Mean glucose (mg/dl) | Change in mean glucose (mg/dl) from baseline to 24 months | 24 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Type 1 Diabetes, HbA1c, Time In Range, Chronic complications, Continuous Glucose Monitoring