montreal_ibd_classification: Montreal Classification for Inflammatory Bowel Disease

In cliot: Clinical Indices and Outcomes Tools

Montreal Classification for Inflammatory Bowel Disease

Description

Generates the Montreal Classification code for Crohn's Disease (CD) or Ulcerative Colitis (UC). For CD, it classifies based on Age at diagnosis (A), Location (L), and Behavior (B). For UC, it classifies based on Extent (E) and Severity (S).

Usage

montreal_ibd_classification(disease_type, age_years = NULL, cd_location = NULL,
                            cd_behavior = NULL, cd_upper_gi = 0, cd_perianal = 0,
                            uc_extent = NULL, uc_severity = NULL)

Arguments

disease_type	String. "crohns" or "uc".
age_years	Numeric. Age at diagnosis (Required for Crohn's). A1: <17, A2: 17-40, A3: >40.
cd_location	String. Disease location (Crohn's). "ileal" (L1), "colonic" (L2), "ileocolonic" (L3).
cd_behavior	String. Disease behavior (Crohn's). "non_stricturing_non_penetrating" (B1), "stricturing" (B2), "penetrating" (B3).
cd_upper_gi	Numeric (0 or 1). Involvement of upper GI tract (L4 modifier). (1 = Yes).
cd_perianal	Numeric (0 or 1). Perianal disease modifier (p). (1 = Yes).
uc_extent	String. Extent of disease (UC). "proctitis" (E1), "left_sided" (E2), "extensive" (E3).
uc_severity	String. Disease severity (UC). "remission" (S0), "mild" (S1), "moderate" (S2), "severe" (S3).

Value

A list containing:

Classification_Code

The resulting Montreal classification string (e.g., "A2 L1 B1" or "E2 S1").

References

Satsangi J, Silverberg MS, Vermeire S, Colombel JF. The Montreal classification of inflammatory bowel disease: controversies, consensus, and implications. Gut. 2006;55(6):749-753. doi:10.1136/gut.2005.082909

Examples

# Example 1: Crohn's Disease
# 25yo, Ileal, Stricturing, No upper/perianal
montreal_ibd_classification("crohns", 25, "ileal", "stricturing", 0, 0)

# Example 2: Crohn's with modifiers
# 16yo, Colonic, Penetrating, Perianal disease present
montreal_ibd_classification("crohns", 16, "colonic", "penetrating", 0, 1)

# Example 3: Ulcerative Colitis
# Left-sided, Moderate severity
montreal_ibd_classification("uc", uc_extent = "left_sided", uc_severity = "moderate")

cliot documentation built on Dec. 1, 2025, 1:06 a.m.