OGTT at Home Using CGM vs at the Clinic
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-70
SponsorLinkoeping University
About this trial
This randomized, crossover study evaluates the feasibility and accuracy of a self-administered oral glucose tolerance test (OGTT) at home using continuous glucose monitoring (CGM) compared to a standard clinic-based OGTT. Participants with prediabetes will undergo both home-based and clinic-based OGTTs, with glucose levels measured via CGM and venous plasma glucose. The primary outcome is the correlation between CGM-based glucose values and standard OGTT results. Secondary outcomes include diagnostic agreement, metabolic hormone associations, and feasibility of home-based testing as a diagnostic tool for dysglycemia.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
- Fasting venous plasma glucose ≥6.1 but ≤6.9 mmol/L
- Non-fasting venous plasma glucose ≥7.8 but ≤11.0 mmol/L
- HbA1c ≥39 but ≤47 mmol/mol
Access to a smart phone which is compatible with the CGM application and has working Bluetooth connectivity
Disqualifiers
- Fasting venous plasma glucose ≥7.0 mmol/L
- Non-fasting venous plasma glucose value ≥11.1 mmol/L
- HbA1c ≥48 mmol/mol
Previous bariatric surgery e.g., gastric by-pass or gastric sleeve surgery
Trial design
Design model
Crossover
Treatments tested in this trial
OGTT at home using CGM
Diagnostic testOGTT at home using CGM
OGTT at the clinic
Diagnostic testOGTT at the clinic
Treatment groups
75 Participants
are divided into 2 treatment groupsGroup A: OGTT at the clinic then at homeExperimental treatment 2 interventions
Group B: OGTT at home then at the clinicExperimental treatment 2 interventions
Trial outcomes
Primary outcomes
1
Diagnostic accuracy of the 2-hour CGM glucose value during home-based OGTT compared with 2-hour venous plasma glucose during clinic-based OGTT
The diagnostic accuracy of the 2-hour interstitial glucose measured by CGM during a home-based oral glucose tolerance test (OGTT) will be evaluated against the 2-hour venous plasma glucose obtained during a clinic-based OGTT (reference standard) for the classification of normoglycemia, prediabetes, and diabetes. The 2-hour CGM value will be defined as the first CGM recording at or within 5 minutes after the 2-hour timepoint (i.e., between 120 and 125 minutes). Diagnostic accuracy will be assessed using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Cohen's kappa coefficient for overall classification agreement, each reported with 95% CIs. Systematic bias and limits of agreement between the two continuous glucose measurements will further be assessed using Bland-Altman analysis.
Time frame
2 hours after the start of the OGTTSecondary outcomes
1
Diagnostic accuracy of the lag-adjusted 2-hour CGM glucose value during home-based OGTT compared with 2-hour venous plasma glucose during clinic-based OGTT
The diagnostic accuracy of a lag-adjusted CGM glucose value during a home-based oral glucose tolerance test (OGTT) will be evaluated against the 2-hour venous plasma glucose during a clinic-based OGTT (reference standard) for the classification of normoglycemia, prediabetes, and diabetes. The lag-adjusted timepoint will be identified from the clinic-based OGTT as the CGM recording between 120 and 140 minutes showing the highest concordance with the 2-hour venous plasma glucose, assessed using Lin's concordance correlation coefficient (CCC), and applied accordingly during the home-based OGTT. Diagnostic accuracy will be assessed using sensitivity, specificity, PPV, NPV, and Cohen's kappa, each with 95% CIs, and Bland-Altman analysis will be used to assess systematic bias and limits of agreement.
Time frame
0-20 minutes after the 2-hour timepoint of the OGTT (lag-adjusted)2
Reproducibility of home-based OGTT using CGM
Reproducibility of the 2-hour CGM glucose value across the two home-based OGTTs will be assessed using intraclass correlation coefficients (ICC), and agreement in glycemic classification (normoglycemia, prediabetes, and diabetes) will be assessed using weighted Cohen's kappa. Both the unadjusted and lag-adjusted 2-hour CGM values will be evaluated.
Time frame
2 hours and 2 hours plus 0-20 minutes lag-adjustment after the start of the OGTTSponsors and contacts
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Source ClinicalTrials.gov