Observational prospective study to validate a new index for early diagnosis of Crohn's disease (CD)

The study will be conducted in Italian referral centers for Crohn's disease and will involve general practitioners (GPs) for RED-Flags Index validation.

The project is divided into two phases.

1. retrospective phase (4 weeks). All the general practitioners participating to the study will extrapolate from their patient's database, the total number of patients with a Crohn's disease diagnosis performed in the past. The date of diagnosis will be indicated. No other information will be provided. These data will be then analyzed to obtain, for each GP, the total number of CD diagnosed in each semester.
2. retrospective phase (6 months). GPs will administer the RED-Flags questionnaire to all patients that meet inclusion and exclusion criteria, after informed consent signature. All these patients will be then referred to the nearest referral center, to be evaluated by a gastroenterologist specialized in CD, to confirm or exclude a CD.

Inclusion Criteria:

1. at least one of the following symptoms, for at least 4 weeks (either continuous or intermittent)

   1. diarrhea (>3 bowel movements per day)
   2. nocturnal diarrhea
   3. weight loss (≥5% of usual body weight)
   4. abdominal pain (chronic or intermittent)
   5. perianal lesions or fistulae or perianal abscess (hemorrhoidal diseases excluded)

2. In the opinion of the investigator, the subject is capable of understanding and complying with protocol requirements. The subject signs and dates a written, informed consent form and any required privacy authorization prior to the initiation of any study procedures.

Exclusion Criteria:

1. known diagnosis of Crohn's disease, ulcerative colitis, chronic diverticulosis or any other gastrointestinal disease
2. any clinical condition that, in the opinion of the investigator, can alter stud results
3. inability to understanding and complying with protocol requirements
4. informed consent not signed and dated by the subject

600 subjects, aged 18-65, requiring general practitioner's advise for gastrointestinal symptoms compatible with Crohn's disease.