Usefulness of Continuous Glucose Monitoring in MODY Diagnosis

Study Overview
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Brief Summary
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Observational study about usefulness of intermittently scanned continuous glucose monitoring (isCGM) in the diagnosis of maturity-onset of the young (MODY) patients.

Detailed Description
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Cross-sectional retrospective analysis of all patients with type 1 diabetes (T1D) in Castilla-La Mancha (south-central Spanish region) using intermittently scanned continuous glucose monitoring (isCGM). This study aimed to asses the usefulness of isCGM in the diagnosis of MODY patients that were previously wrongly diagnosed as T1D patients. The following glycometrics were taking into account as MODY predictors: time in range (70-180 mg/dL >70%, Glucose Management Index <7% y Coefficient of variation <36%. Patient´s clinical records of subjects meeting these glycometric criteria were reviewed for clinical suspicious of MODY (diagnosis before 35 years of age, first-degree family history of diabetes, negative pancreatic autoimmunity, preserved pancreatic beta cell function. Those patients meeting isCGM and clinical suspicious criteria were offered a diagnostic test for MODY. The relationship between the qualitative outcome variable (MODY presence) and the quantitative variables will be performed using Student's t-test and ANOVA in situations of good fit with normality, and the Mann Whitney U and Kruskal Wallis when there is not a good fit with normality, and the Mann Whitney U and Kruskal Wallis when there is not.A P value < 0.05 was considered statistically significant. The protocol was approved by the reference Castilla-La Mancha Public Health Institute Ethic Committee.

Official Title
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Usefulness of Intermittently Scanned Continuous Glucose Monitoring in the Diagnosis of Maturity-onset Diabetes of the Young (MODY) Patients

Conditions
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Type 1 Diabetes, MODY

Intervention / Treatment
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* Device: Intermittenly scanned continuous glucose monitoring
* Other: MODY genetic diagnostic test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Presence of T1D. Age equal or higher than 18 years old. In treatment with isCGM system. Active data in Libreview. isCGM use >70% of the possible time of use (isCGM data quality criteria). Time in range >70%, glucose management index <7% and coefficiente of variation <36% in the last 14 days glucometric recording. Exclusion Criteria: Not receiving treatment with isCGM. Diagnosis of T1D in the last three years. Gestation in progress or programmed pregnancy.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Type 1 diabetes patients<br>All type 1 diabetes patients using intermittently scanned continuous glucose monitoring (isCGM) in Castilla-La Mancha (Spain). | Device: Intermittenly scanned continuous glucose monitoring<br>* Use of Intermittenly scanned continuous glucose monitoring (FreeStyle Libre) and meeting the glycometric data criteria: Time in range 70-180 mg/L >70% Glycemic management index <7% Coefficient of variation <36%<br>Other: MODY genetic diagnostic test<br>* Those patients fulfilling the glycometric data criteria and with clinical MODY suspicion: diagnosis before 35 years of age first-degree family history of diabetes. negative pancreatic autoimmunity (Ac GAD, IA-2A and Ac ZnT8) preserved pancreatic beta cell function defined as C-peptide > 0.2 ng/mL in the presence of plasma glycemia >140 mg/dL). Those patients who meet the previous criteria will proceed to the MODY genetic diagnostic test.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Positive predictive value | Positive predictive value of the combination of the glucometric variables TIR>70%, GMI <7% and CV <36% in the diagnosis of MODY. Units % (min 0, max 100) | 14 days | 
| Negative predictive value | Negative predictive value of the combination of the glucometric variables TIR>70%, GMI <7% and CV <36% in the diagnosis of MODY. Units % (min 0, max 100) | 14 days | 
| Sensitive | Sensitive of the combination of the glucometric variables TIR>70%, GMI <7% and CV <36% in the diagnosis of MODY. Units % (min 0, max 100) | 14 days | 
| Specificity | Specificity of the combination of the glucometric variables TIR>70%, GMI <7% and CV <36% in the diagnosis of MODY. Units % (min 0, max 100) | 14 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percetage of wrongly diagnosed type 1 diabetes patients | To assess the percentage of MODY patients with misdiagnosis of DM1. Units % (min 0, max 100) | 14 days | 
| Time in range of interstitial glucose in MODY patients | To assess the percetage of time in range (70-180 mg/dL, 3.9-10 mmol/L) of interstitial glucose in patients finally diagnosed as MODY. Units % (min 0, max 100) | 14 days | 
| Time above range of interstitial glucose in MODY patients. | To assess the percentage of time above range (>180 mg/dL, >10 mmol/L) of patients finally diagnosed as MODY. Units % (min 0, max 100) | 14 days | 
| Time beloww range of interstitial glucose in MODY patients. | To assess the percentage of time bellow range (<70 mg/dL, <3.9 mmol/L) of patients finally diagnosed as MODY. Units % (min 0, max 100) | 14 days | 
| Coefficient of variation of interstitial glucose in MODY patients. | To assess the coefficient of variations of patients finally diagnosed as MODY. Units % (min 0, max 100) | 14 days | 
| isCGM daily scan frequency in MODY patients | To analyze the use of iCGM in patients finally diagnosed as MODY through daily frequency of scanning (number daily scans, min 0-max 100). | 14 days | 
| Percentage of iCGM in MODY patients | To analyze the percentage of iCGM use in patients finally diagnosed as MODY (% time in use, units %, mix 0- max 100). | 14 days |