HbA1c in two unit systems, CGM summary metrics, hypoglycaemia events by level and daily insulin doses. Capture structures each one so glycaemic endpoints and safety tables come out of the database without recoding.
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Event date and time
Lowest glucose
Level
Nocturnal?
Treatment given
What matters in diabetes trials
Glycaemic endpoints
HbA1c is reported in two unit systems: percent (NGSP/DCCT), common in the US, and mmol/mol (IFCC), common in Europe and many other countries. Multi-country trials that let sites enter whichever their lab reports end up with mixed units in one column. Fix the unit on the form, convert at source using the lab report, or collect the value with a unit field and convert centrally, but decide before the first entry.
Continuous glucose monitoring has changed what diabetes trials can measure. Instead of a quarterly average, CGM gives the proportion of time spent in, below and above target ranges, and how variable glucose is. International consensus recommends time in range of 70 to 180 mg/dL (3.9 to 10.0 mmol/L), with targets for most adults of more than 70% of time in range and less than 4% below 70 mg/dL.
Raw CGM traces usually stay in the device platform or go to a central reader. What the eCRF needs are the summary metrics for each assessment period: percent time in range, below and above range, mean glucose, glucose management indicator, coefficient of variation, and the percentage of data captured (low wear time can invalidate a period). Record them as number fields with fixed units and ranges on a form placed at each assessment visit.
Capture manages reference ranges per laboratory, by sex and age, flags out-of-range values at entry, and routes alert values (for example very high fasting glucose or potassium) to the medical monitor, with acknowledgement recorded. See lab data and reference range management.
Time in range
74%
Below 70
3.1%
CGM wear
93%
Target above 70%
Target below 4%
Study build
| Form | Type | Key fields | Built-in help |
|---|---|---|---|
| Glycaemic labs | Visit form | HbA1c, fasting plasma glucose, lipids | Lab ranges by sex and age, alert values |
| CGM summary | Visit form | Time in, below and above range, mean glucose, CV, wear time | Range checks on each metric |
| Hypoglycaemia events | Log form | Date and time, lowest glucose, level, nocturnal, treatment | Level as structured choice |
| Insulin and glucose-lowering doses | Log or diary | Drug, dose, units, time | Participant diary option |
| Anthropometrics | Visit form | Weight, height, waist, hip | BMI and waist-hip ratio calculated |
| Renal function | Visit form | Creatinine, age, sex | eGFR CKD-EPI 2021 and creatinine clearance calculated |
| Adverse events | Log form | Term, onset, severity, seriousness, causality | Minimum dataset enforced |
Between visits
Many diabetes trials ask participants to log fingerstick glucose, insulin doses or hypoglycaemia symptoms between visits. Capture runs these as recurring diaries in the phone browser, with completion windows and reminders that respect quiet hours, so the data arrives while it is still fresh.
Derived values
Diabetes trials use renal function for eligibility and dose decisions, and weight-related measures as secondary endpoints. Capture calculates them read-only as sites enter the inputs, so they never disagree with the source values.
BMI (Body Mass Index)
Auto-derivedHeight (cm)
172
Weight (kg)
68.5
Result
23.2 kg/m²
Reference: WHO · shown read-only during data entry
Build them in the free sandbox and enter a test event.
Dosing
Many diabetes trials titrate doses to a glucose target, for example adjusting basal insulin weekly based on fasting glucose, or escalating a GLP-1 receptor agonist in steps as tolerated. The titration algorithm is part of the protocol, and whether sites followed it affects both efficacy and hypoglycaemia outcomes. That makes dose data an analysis variable, not an administrative detail.
Capture the inputs and the decision: the glucose values the algorithm uses, the dose prescribed and the dose actually taken. When participants self-titrate, a short diary for fasting glucose and dose keeps the record contemporaneous; when sites titrate, a dose adjustment log with a reason field shows whether the algorithm was followed. Deviations from the algorithm can then be reviewed centrally rather than discovered at the end.
Level 2 and level 3 hypoglycaemia are key safety outcomes, often analysed as event rates per patient-year. That requires every event as its own record with date and time, not a count per visit. A log form keeps each event separate, and custom-value checks on level 3 events can raise a high-priority query so the site confirms details and assesses whether the event is serious. See the adverse event eCRF template for the SAE path.
Study build
% or mmol/mol per field, decided before first entry.
Which summary metrics, which period, and the minimum wear time for a valid period.
One record per event with level, time and treatment.
Glucose inputs, prescribed dose and actual dose, with reasons for deviations.
Per laboratory, by sex and age, with alert limits.
eGFR, BMI and waist-hip ratio from the built-in calculators.
Change from baseline in HbA1c, often at around 24 to 26 weeks, with CGM metrics, fasting glucose, body weight and hypoglycaemia as key secondary endpoints.
Either, but only one per field. Fix the unit on the form or collect a unit field and convert centrally, and decide before data entry starts.
On a log form with date and time, lowest glucose, level (1, 2 or 3), whether it was nocturnal and the treatment given.
Record CGM summary metrics for each assessment period as structured number fields. Raw traces usually remain in the device platform or with a central reader.
Yes. eGFR (CKD-EPI 2021) and creatinine clearance (Cockcroft-Gault) are built-in calculated fields.
Yes. The free sandbox has every feature with no credit card.
Keep exploring
EDC for GLP-1 and weight trials
Obesity and incretin studies.
EDC for metabolic studies
Metabolic research more broadly.
Lab data and reference ranges
Ranges by sex and age.
Nutrition research software
Diet and glucose studies.
What is a reference interval?
Normal ranges explained.
Vital signs eCRF template
Weight, BP and BMI.
Structured labs, CGM metrics and hypoglycaemia logs. Free sandbox.