Crohn's Therapy Decision Tree

Objective: Provide direction regarding choice of therapy for patients with Crohn’s disease.

Patient population: Adult patients (>18years) with known diagnosis of Crohn’s disease.

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Therapy decisions are based on anatomic location of disease, severity of disease, disease complications, extra-intestinal manifestations of the disease, other comorbidities, and patient preference.  Treatment goals include induction and maintenance of remission.


New therapies are constantly being developed and should be considered.


Crohn’s disease (CD) is a chronic inflammatory condition that affects any portion of the gastrointestinal tract from the mouth to the anus and perianal region.  Extra-intestinal manifestations and/or complications can occur. The most commonly affected parts of the GI tract are the terminal ileum and colon. Inflammation is typically segmental, asymmetrical and transmural. Most patients are diagnosed with an inflammatory phenotype at first presentation, but over time, complications such as strictures, fistulas or abscesses can develop in over half of patients.  These complications often require surgery. 

Types of Crohn's Disease

The Montreal classification is commonly used to classify the major phenotypic features of CD based on age at diagnosis, location of the disease and disease behaviour.

*L4 is a modifier that can be added to L1-3 when concomitant upper GI disease is present

**B1 category should be considered ‘interim’ until a pre-specified time has elapsed from the time of diagnosis. Such a time period may vary from study to study (e.g. 5-10 years is suggested) but should be defined in order for B1 behavior to be considered ‘definitive.’ GI—Gastrointestinal

***p is a modifier that can be added to B1-3 when concomitant perianal disease is present

Prior to therapy decisions, the following assessments should be carried out and treatment goals discussed with the patient.

Goal of therapy: deep and prolonged remission with long-term goal of preventing complications and halting the progressive course of the disease. Deep remission is a combination of symptomatic and objective markers of remission.

Management of mild Crohn's disease

Mild disease defined as CDAI <220 or HBI ≤7. Following complete evaluation with endoscopy (ileocolonoscopy +/- upper endoscopy) and/or imaging (enterography, capsule endoscopy, and/or intestinal ultrasound), and lab tests, the choice of treatment will in part depend on the distribution of disease as well as disease activity. 

Management of moderate to severe Crohn's disease

Other Resources

For IBD Providers

Inflammatory Bowel Disease: Drug Comparison chart

For Patients

Crohn’s and Colitis Canada: IBD journey webpage

UpToDate® - Patient education: Crohn’s disease (Beyond the Basics) (freely accessible)


Nguyen et al. Positioning Therapies in the Management of Crohn’s Disease. Clin Gastroenterol and Hepatol 2020; 18(6):1268-79

Panaccione et al. Canadian Association of Gastroenterology Clinical Practice Guidelines for the Management of Luminal Crohn’s Disease. J Can Assoc Gastroenterol 2019; 2(3): e1-e34

Lichtensein et al. ACG Clinical Guideline: Management of Crohn’s Disease in Adults. Am J Gastroenterology 2018; 113:481-517

Sandborn W.J. Evaluation and Treatment: Clinical Decision Tool Gastroenterology 2014; 147:702-705

Turner D, Ricciuto A, Lewis A, et al. STRIDE-II: An Update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) Initiative of the International Organization for the Study of IBD (IOIBD): Determining Therapeutic Goals for Treat-to-Target strategies in IBD. Gastroenterology. 2021;160(5):1570-1583.

2024 ECCO guidelines (expected Jan 2024)

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