TABLE 1.

Comparison of commonly used ulcerative colitis disease activity indexes

	Activity level
Clinical index	Mild	Moderate	Severe
American College of Gastroenterology (80)	<4 stools/day ± blood, normal ESR and no sign of toxicity	≥4 stools/day ± blood and minimal signs of toxicity	>6 stools/day ± blood, evidence of toxicity (fever, tachycardia, anemia or elevated ESR)
Truelove and Witts (81)	<5 bowel movements/day, small amounts of blood in the stool, no fever, no tachycardia, mild anemia (>75%, approximately 100 g/L) and ESR <30	Intermediate condition between mild and severe	≥6 bowel movements/day, large amounts of blood in the stool, fever (>37.5°C), pulse (>90 beats/min), anemia (hemoglobin >75% of baseline) and ESR >30
Mayo score (82)	Score 3 to 5	Score 6 to 9	Score 10 to 12
≤2 indicates clinical remission if sustained for three days	1 to 2 more stools/day than normal Some blood in <50% of stools	3 to 4 more stools/day than normal Some blood in stools most of the time	≥5 more stools/day than normal Rectal bleeding, passing blood-only stools
Each of the four subcategories (stools/day, bleeding, endoscopy and physician’s global assessment) are rated 0 to 3 in increasing severity. The sum is the final score ranging from 0 to 12.	Minimal rectal bleeding Endoscopy shows erythema, mild friability and/or decreased vascular pattern Physician’s global assessment is mild activity of disease	Endoscopy shows marked erythema, lack of vascular pattern, definite friability and mucosal erosions Physician’s global assessment is moderate disease activity	Endoscopy shows spontaneous bleeding and mucosal ulcerations Physician’s global assessment is severe disease activity
C-reactive protein (83)	≥0 mg/L	≥3 mg/L	≥12 mg/L

ESR Erythrocyte sedimentation rate determined using the Wintrobe method