How to use it
Ask about the previous day: general well-being, abdominal pain and the number of liquid or soft stools. Examine for an abdominal mass. Then add one point for each complication present: arthralgia, uveitis, erythema nodosum, aphthous ulcers, pyoderma gangrenosum, anal fissure, new fistula or abscess.
The stool count is required. Enter 0 if there were none. The tool won’t show a result until every item is answered.
Reading the result
| HBI | Usual label |
|---|---|
| Below 5 (0–4) | Remission |
| 5–7 | Mild |
| 8–16 | Moderate |
| Above 16 | Severe |
- Remission: an HBI of 4 or less corresponds to a CDAI of 150 or less (Vermeire 2010). STRIDE-II accepts HBI below 5 as an alternative to PRO2 for clinical remission.
- Response: a fall of 3 or more corresponds to a 100-point fall in the CDAI (Vermeire 2010).
- The bands are benchmarks mapped from the CDAI, not separately validated categories.
Limits
- It measures symptoms, not inflammation. Symptom scores track endoscopic activity poorly: in SONIC, only 72 of 136 patients (53%) in clinical remission by CDAI had mucosal healing, and some with healed mucosa still had symptoms (Peyrin-Biroulet 2014). The HBI is a simplified CDAI and shares this limit. Treat-to-target decisions need objective markers: calprotectin, CRP, endoscopy or intestinal ultrasound.
- Stool count is confounded by an ileostomy, previous resection, short bowel, bile-acid diarrhoea and overlapping IBS.
- Perianal disease is under-weighted. A new fistula or abscess adds a single point. Use the PDAI for perianal activity.
- Interpret a single score in context; follow the same patient over time.