Clinical decision support
Practice guidelines and risk calculators
Third-party guidelines and prediction tools relevant to Crohn’s disease, each independently verified against PubMed. These are external documents and tools — linked, not reproduced, and not evidence-gated by this site.
Read the access and validation labels. Very few published IBD prediction tools are simultaneously a live free calculator, externally validated, and validated for the decision you are about to make. Where a tool is formula-only, or was validated only in its derivation cohort, that is stated rather than hidden behind a link. 3 further item(s) found by this review are withheld pending clinician sign-off rather than published unverified.
Practice guidelines
- ECCO Guidelines on Therapeutics in Crohn's Disease: Surgical Treatment
- ACG Clinical Guideline: Management of Crohn's Disease in Adults
- ECCO Guidelines on Therapeutics in Crohn's Disease: Medical Treatment
- AGA Living Clinical Practice Guideline on the Pharmacologic Management of Moderate-to-Severe Crohn's Disease
- The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Surgical Management of Crohn's Disease
- The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula
- ECCO-ESGAR-ESP-IBUS Guideline on Diagnostics and Monitoring of Patients with Inflammatory Bowel Disease: Part 1
- AGA Clinical Practice Guideline on the Role of Biomarkers for the Management of Crohn's Disease
- British Society of Gastroenterology guidelines on inflammatory bowel disease in adults: 2025
- ESPEN guideline on Clinical Nutrition in inflammatory bowel disease
- Crohn's disease: management (NG129)
Risk calculators and prediction tools
- Postoperative recurrence predictive model / nomogram, biologic era (Allez / Hammoudi) Note: AUC 0.72 — risk-stratification only, not a substitute for the guideline-mandated ileocolonoscopy in the first postoperative year. Predicts ENDOSCOPIC, not clinical, recurrence. No hosted web calculator exists; the nomogram must be read off the paywalled paper. Clinically important dissonance: this contemporary cohort (n=632, 78% biologic-exposed) did NOT reproduce penetrating phenotype as a risk factor, although guidelines still list it.
- MONITOR index (MRI in Crohn's Disease to Predict Postoperative Recurrence) Note: Small: derived from 73 MRI datasets at a single French centre, with a small independent validation cohort. At the proposed threshold (>= 1) specificity is only 55% — it will over-call recurrence. Requires a radiologist to score seven items; no calculator is hosted anywhere.
- Crohn's Disease Activity Index (CDAI) Note: Explicitly NOT valid in the population this site serves: it performs poorly in stricturing and fistulizing disease, after extensive ileocolonic resection, and in patients with a stoma. It is a symptom score that correlates poorly with endoscopic activity, and MDCalc itself notes it is unaware of any outcome-validated algorithm built on the score. It measures how a patient feels, not surgical risk.
- Harvey-Bradshaw Index (HBI) Note: Inherits every CDAI limitation (symptom-only, blind to transmural and endoscopic disease, unreliable post-resection or with a stoma). The claim of equivalence to CDAI rests on a correlation coefficient of 0.93, which is not the same as agreement; the < 5 remission cut-off is conventional, not outcome-derived. No maximum score, since liquid stool count is unbounded.
- Perianal Disease Activity Index (PDAI) Note: Validated only within its own single-centre derivation study (37 patients, 124 visits) against physician and patient global assessment; I found no independent external validation, and heavy use as a trial endpoint is not the same thing. Contains no imaging component, so it cannot distinguish a clinically closed tract from a radiologically healed one. There is no free hosted calculator — it is not on MDCalc; you must reproduce the five items from the 1995 paper.
- ACS NSQIP Surgical Risk Calculator Note: Externally validated in several surgical populations but I found NO external validation in Crohn's or IBD bowel resection — treat its output in a CD patient as unvalidated. It cannot see the variables that actually drive CD operative risk: biologic exposure, steroid dose and duration (only a binary 'steroid use' field), severity of malnutrition, intra-abdominal abscess or phlegmon, penetrating phenotype, and reoperative/hostile abdomen. Calibration has already been shown to drift in adjacent colorectal cohorts (complications underestimated in colorectal liver metastasis, non-home discharge overestimated in elderly colorectal cancer). Derivation PMID left blank because the calculator is a maintained registry model, not a single citable derivation paper.