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OpenTrials
Completed

NCT Number: NCT07614139

Continuous Glucose Monitoring Alerts, Accuracy, and Patient Outcomes in Adults With Inherited Metabolic Disorders

The goal of this clinical trial is to learn if a continuous glucose monitor (CGM) with predictive alerts works better than a CGM with standard alerts to prevent low blood sugar (hypoglycemia) in adults with inherited metabolic disorders (IMDs), such as glycogen storage disorders (GSDs) and congenital hyperinsulinism (CH).

The main questions it aims to answer are:

Does a CGM with predictive alerts lower the time spent with low blood sugar compared to a CGM with standard alerts? Do participants feel better and behave differently when using a CGM with predictive alerts? How accurate are the two CGM devices in this group of people? Researchers will compare two CGM devices - Dexcom G7 (with predictive and standard alerts) and Dexcom ONE+ (with standard alerts only) - to see if predictive alerts help reduce low blood sugar episodes and improve quality of life.

Participants will:

Wear each CGM device for 30 days Have a 30-day break between the two devices Check blood sugar levels and record food intake Complete questionnaires about their experience with each device

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Key information

Conditions

Glycogen Storage Disease Carbohydrate Metabolism, Inborn Errors Congenital Hyperinsulinism Congenital Hyperinsulinism (CHI) Congenital, Hereditary, and Neonatal Diseases and Abnormalities Digestive System Diseases Genetic Diseases, Inborn Glucose Metabolism Disorders Hyperinsulinism Hypoglycemia Infant, Newborn, Diseases Metabolic Diseases Metabolism, Inborn Errors Nutritional and Metabolic Diseases Pancreatic Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University Hospital of Padova

Padova, 35128, Italy

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18 years or older
  • Genetic or biochemical diagnosis of Glycogen Storage Disease (GSD) or Congenital Hyperinsulinism (CH)
  • At least one clinical and biochemical follow-up at the hospital outpatient service within the last one or two years
  • Ability to sign informed consent and comply with study procedures

Exclusion criteria

  • Inability to sign informed consent or comply with study procedures

Treatment and study plan

Continuous glucose monitor with threshold and predictive alerts (Dexcom G7)

Device

The Dexcom G7 is a CE-marked continuous glucose monitoring (CGM) device worn for 30 days. It provides real-time interstitial glucose readings every 5 minutes. The device offers both threshold-based alerts, activated when glucose levels fall below or rise above pre-set values, and predictive alerts, activated when glucose levels are predicted to reach a threshold within 20 minutes. The low glucose alert threshold was set at 70 mg/dL for all participants.

Continuous glucose monitor with threshold-only alerts (Dexcom ONE+)

Device

The Dexcom ONE+ is a CE-marked continuous glucose monitoring (CGM) device worn for 30 days. It provides real-time interstitial glucose readings every 5 minutes. The device offers threshold-based alerts only, activated when glucose levels fall below or rise above pre-set values, without predictive alert functionality. The low glucose alert threshold was set at 70 mg/dL for all participants.

Primary outcomes

  1. Time Below Range (TBR)

    Time frame: 30 days per device (total study duration: approximately 90 days including washout period)

    Percentage of time spent with interstitial glucose levels below 70 mg/dL, as measured by continuous glucose monitoring (CGM). TBR is reported at two thresholds: TBR1 (54-69 mg/dL) and TBR2 (<54 mg/dL), both expressed as percentage of monitoring time (%), over 30 days for each device.

    Unit of Measure: % of monitoring time

Secondary outcomes

  1. Time in Range (TIR)

    Time frame: Time Frame: 30 days per device

    Percentage of time spent with interstitial glucose levels within the target range of 70-140 mg/dL, as measured by CGM over 30 days for each device. Expressed as percentage of monitoring time (%).

    Unit of Measure: % of monitoring time

  2. Time Above Range (TAR)

    Time frame: Time Frame: 30 days per device

    Percentage of time spent with interstitial glucose levels above 140 mg/dL, as measured by CGM over 30 days for each device. Expressed as percentage of monitoring time (%).

    Unit of Measure: % of monitoring time

  3. Mean Glucose Level

    Time frame: Time Frame: 30 days per device

    Mean interstitial glucose levels calculated over 24 hours and during nighttime (00:00-07:00), as measured by CGM over 30 days for each device.

    Unit of Measure: mg/dL

  4. Sensor Accuracy - median absolute relative difference (MARD)

    Time frame: 30 days per device

    Accuracy of CGM readings compared to capillary blood glucose reference values (Accu-Check Instant, Roche), expressed as Median Absolute Relative Difference (MARD). Capillary and CGM values matched within a ±5-minute time window.

    Unit of Measure: %

  5. Dietary Intake Assessment

    Time frame: 7 days per device

    Total daily energy intake measured during each device wear period Unit of Measure: kcal/day Total daily macronutrient intake measured during each device wear period Unit of Measure: grams/day Daily uncooked cornstarch intake measured during each device wear period Unit of Measure: grams/day All dietary intakes were assessed by 7-day food diary analyzed with Metadieta® software (Meteda Srl, Italy), completed during CGM monitoring and reviewed by an experienced metabolic dietitian.

  6. Hypoglycemia Fear and Protective Behaviors Assessment

    Time frame: baseline and after 30 days per device

    Assessed using the Hypoglycemia Fear Survey (HFS), comprising two subscales: Worry (HFS-W) and Behavior (HFS-B). Each item scored 0-4; total range 0-132; higher scores indicate greater fear of hypoglycemia and more behaviors engaged to avoid hypoglycemic episodes.

    Unit of Measure: Score (0-132)

  7. Hypoglycemia Awareness Assessment

    Time frame: baseline and after 30 days per device

    Assessed using the Clarke Hypoglycemia Awareness Questionnaire (CHAQ), comprising 8 items on hypoglycemia awareness and recognition. Range 0-7; scores ≥4 indicate impaired awareness of hypoglycemia; higher scores indicate worse hypoglycemia awareness.

    Unit of Measure: Score (0-7)

  8. Sleep Quality Assessment

    Time frame: Baseline and after 30 days per device

    assessed using the Pittsburgh Sleep Quality Index (PSQI), a self-report questionnaire assessing sleep quality and disturbances over the previous month. Global score ranges from 0 to 21; scores >5 indicate poor sleep quality; higher scores indicate worse sleep quality.

    Unit of Measure: Score (0-21)

  9. Health-Related Quality of Life Assessment

    Time frame: Baseline and after 30 days per device

    Assessed using the 12-Item Short Form Health Survey (SF-12), yielding Physical Component Summary (PCS) and Mental Component Summary (MCS) standardized scores. Higher scores indicate better quality of life.

    Unit of Measure: Standardized score for Italian population

  10. Body Mass Index (BMI)

    Time frame: Baseline and after 30 days per device

    Height measured at baseline; weight measured at the start and end of each CGM period using a calibrated mechanical scale (Seca 700). BMI calculated as weight (kg)/height² (m²), interpreted according to WHO classification: <18.5 underweight; 18.5-25 healthy weight; 25-30 overweight; >30 obesity.

    Unit of Measure: kg/m²

Sponsors and collaborators

Lead sponsor

University Hospital Padova

Other

Collaborators

  • University of Padova

Registry information

Official study title

Continuous Glucose Monitoring Alerts, Accuracy, and Patient Outcomes in Adults With Inherited Metabolic Disorders Prone to Hypoglycemia

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
May 29, 2026
Registry last updated
May 29, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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