Therapeutic area · GastroenterologyUpdated September 28, 2026

EDC for gastroenterology and IBD trials

IBD endpoints combine what participants record at home, such as stool frequency and bleeding, with endoscopy read centrally. Capture runs the daily diary on participants' phones and keeps visit, endoscopy and lab data in the same study.

  • Daily stool and bleeding diary
  • Endoscopy result forms
  • Components kept for scoring

Free sandbox · No credit card · 21 CFR Part 11 aligned

Daily bowel diary

Monday · Day 5 of 7 before Week 8 visit

Number of stools today

4

Blood in stool

NoneStreaks, less than half the timeObvious blood most of the timeBlood alone

Worst abdominal pain today

012345678910
Diary days before each visit feed the score

What matters in GI and IBD trials

  • Ulcerative colitis trials commonly use the modified Mayo score: stool frequency, rectal bleeding and endoscopic subscores, each 0 to 3. Clinical remission typically requires low scores on all three.
  • Crohn's disease trials use patient-reported stool frequency and abdominal pain (PRO2) with endoscopic response as co-primary endpoints; the older CDAI remains common as a secondary.
  • Both depend on daily diaries over the days before each visit, so missing diary days directly affect the endpoint.
  • Endoscopy is usually read centrally by blinded readers to reduce variability.
  • IBS trials use composite weekly responder endpoints combining abdominal pain with stool consistency or frequency, often with the Bristol stool scale.

Study design

Diary windows decide the endpoint

Mayo stool frequency and rectal bleeding subscores, CDAI and PRO2 are calculated from daily diary entries over a defined number of days before a visit, often the three most recent valid days out of the seven before the visit, excluding days affected by bowel preparation or endoscopy. If participants forget to fill in the diary, or fill it in retrospectively, the visit score is unreliable or missing.

That makes the diary schedule as important as the visit schedule. Daily entries with completion windows, reminders and a clear view of which participants are missing days before an upcoming visit let sites intervene in time. The stool frequency subscore is also relative to each participant's normal frequency, which must be recorded at baseline.

Endoscopy

Record the procedure date, preparation quality and local read on a site form, and the central read result when it arrives. Keeping local and central reads as separate variables shows where they disagree and makes it clear which one the endpoint uses.

Schedule of assessments · UC induction trial
AssessmentScrBLW2W4W8W12
Daily diaryDDDDDD
Endoscopy (central read)
Physician global assessment
Labs (CRP, faecal calprotectin)
IBD quality of life

D = daily diary entries

Daily diary

Protect the diary days that matter

Participants complete a short diary each evening from a secure link on their phone, with no app. Completion windows stop back-filling, a reminder ladder prompts missed entries while respecting quiet hours, and the dashboard flags at-risk participants so sites can call before diary days are lost.

  • Daily recurring diary with a completion window.
  • Reminders by email or SMS.
  • At-risk participants flagged on the dashboard.
Patient diary software
1

When due

18:00

Your evening diary is open

2

Next day

18:00

Reminder: your diary is still open

3

Final notice

21:30

Last chance before the window closes

Quiet hours

22:00 to 08:00 in the participant's time zone

Stops

As soon as the task is completed

Build a bowel diary and endoscopy form

Try the diary on your phone in the free sandbox.

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Endpoints

GI endpoints and their components

ConditionEndpointComponents
Ulcerative colitisModified Mayo score, clinical remissionStool frequency and rectal bleeding (diary), endoscopic subscore (central read)
Ulcerative colitisHistological and endoscopic improvementBiopsy histology scores and endoscopy
Crohn's diseasePRO2 remission and endoscopic responseStool frequency and abdominal pain (diary), SES-CD (central read)
Crohn's diseaseCDAISeven-day diary items, clinical findings, haematocrit, body weight
IBSWeekly composite responderDaily abdominal pain and stool consistency or bowel movements

Definitions vary by protocol and regulator. Write the exact derivation rules in the analysis plan.

Biomarkers and safety

Calprotectin, CRP and infection screening

Faecal calprotectin and C-reactive protein track inflammation between endoscopies and are common secondary endpoints. Record them with units, sample dates and the laboratory, because calprotectin assays differ. Stool testing for infection, particularly Clostridioides difficile, is usually required at screening and during flares, since infection can mimic a flare.

Immunosuppressive treatments also need safety labs and infection monitoring. A lab table with reference ranges and range checks keeps repeated values consistent across sites. See the lab results eCRF template.

Study build

GI study build checklist

Diary derivation rules

Which days count, exclusions for bowel preparation.

Baseline normal frequency

Recorded for the stool frequency subscore.

Endoscopy data

Local and central reads as separate variables.

Physician global

Scheduled if part of the score.

Biomarkers

Calprotectin and CRP with assay details.

Infection screening

Stool tests at screening and flares.

FAQ

Questions teams ask before they switch

Something not covered here? Ask us directly.

What is the modified Mayo score?

A score for ulcerative colitis made up of stool frequency, rectal bleeding and endoscopic subscores, each 0 to 3.

What is PRO2 in Crohn's disease?

A patient-reported measure combining stool frequency and abdominal pain from daily diaries, used with endoscopic response as co-primary endpoints.

Why are diaries so important in IBD trials?

Key endpoints are calculated from diary entries in the days before each visit, so missing days affect the score.

Is endoscopy read centrally?

Usually, by blinded central readers. Local and central reads should be kept as separate variables.

Do participants need an app?

No. The diary opens in the phone browser from a secure link.

Can I try it free?

Yes, in the free sandbox with every feature.

GI endpoints built on complete diaries

Daily diaries with windows and reminders. Free sandbox.

Build your GI study free