C D A I
Clinical remission
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Evidence-based calculations Used in clinical settings worldwide Regular monitoring recommended
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🏥 Sample Clinical Scenarios
👤 Patient Information
📋 Symptoms (Past 7 Days)
🩺 Physical Findings & Medications
⚠️ Extraintestinal Complications (Check all present)
Crohn's Disease Activity Index
Clinical Assessment
Component Breakdown
Visual Analysis
CDAI Score
Component Scores
Clinical Recommendations
Step-by-Step Calculation
CDAI uses 8 variables with different weighting factors to assess disease activity.
Number of liquid stools in past 7 days: 3
Score: 3 × 2 = 6
Daily average pain rating: 1 (Mild)
Score: 1 × 5 × 7 days = 35
Daily average well-being: 1 (Slightly below par)
Score: 1 × 7 × 7 days = 49
No extraintestinal complications
Score: 0 × 20 = 0
Antidiarrheal medication use: No
Score: 0 × 30 = 0
Abdominal mass: None (0)
Score: 0 × 10 = 0
Current hematocrit: 42%, Expected for male: 47%
Deviation: 47 - 42 = 5 (negative values = 0)
Score: 5 × 6 = 30.0
Current: 70 kg, Ideal: 75 kg
Deviation: ((75.0 - 70.0) / 75.0) × 100 = 6.7%
Score: 6.7 × 1 = 6.7
Total = 6 + 35 + 49 + 0 + 0 + 0 + 30.0 + 6.7
CDAI = 127
Category: Remission (< 150)
Significance: Disease under control, maintenance therapy effective
CDAI Severity Categories
| Score Range | Category | Description | Clinical Significance |
|---|---|---|---|
| < 150 | Remission | Clinical remission | Disease under control, maintenance therapy effective |
| 150-220 | Mild-Moderate | Mildly to moderately active disease | Symptomatic disease requiring treatment adjustment |
| 220-450 | Moderate-Severe | Moderately to severely active disease | Significant disease activity, aggressive treatment needed |
| > 450 | Severe-Fulminant | Severe to fulminant disease | Critical disease state, hospitalization likely needed |
For informational purposes only — not medical advice. Consult a healthcare professional before acting on results.
🏥 Health Facts
— WHO
— CDC
📊 What is the CDAI?
The Crohn's Disease Activity Index (CDAI) was developed in 1976 at the Midwest Regional Health Center to quantify symptoms in patients with Crohn's disease. It remains the gold standard for clinical trials and treatment response assessment.
The index combines 8 clinical variables with different weighting factors to produce a composite score that correlates with disease activity and helps guide treatment decisions.
Eight Components
- Liquid stools: Number in past week (×2)
- Abdominal pain: Daily rating averaged (×5)
- Well-being: Daily rating averaged (×7)
- Complications: Extraintestinal manifestations (×20)
- Antidiarrheal: Use of medications (×30)
- Abdominal mass: Presence on exam (×10)
- Hematocrit: Deviation from normal (×6)
- Weight: Deviation from ideal (×1)
🧮 How to Calculate CDAI
- Track symptoms for 7 days: Daily liquid stools, pain rating (0-3), well-being (0-4)
- Sum weekly values: Total liquid stools, sum daily ratings
- Assess complications: Check for extraintestinal manifestations
- Physical exam: Evaluate for abdominal mass
- Lab values: Recent hematocrit
- Weight assessment: Compare to ideal body weight
- Apply multipliers: Each component has a specific weighting factor
⏰ When to Use CDAI
Clinical Applications
- Assess disease activity
- Define clinical remission (<150)
- Monitor treatment response
- Clinical trial endpoints
- Guide therapy escalation
Limitations
- Subjective symptom reporting
- Doesn't correlate with endoscopy
- Requires 7-day symptom diary
- Less useful for isolated perianal disease
- Weight component less reliable
📐 CDAI Scoring Interpretation
| Score Range | Interpretation | Clinical Significance |
|---|---|---|
| < 150 | Remission | Disease controlled, maintenance therapy |
| 150-220 | Mild-Moderate | Active symptoms, consider step-up |
| 220-450 | Moderate-Severe | Significant activity, aggressive therapy |
| > 450 | Severe-Fulminant | Critical, hospitalization likely |
Response to Treatment: A decrease of >70 points indicates clinical response. A decrease of >100 points indicates significant response.
🎬 Educational Resources
IG-IBD Interactive CDAI Calculator
Comprehensive interactive tool with detailed explanations of each CDAI component and clinical interpretation guidelines.
IG-IBD CalculatorMerck Manual: CDAI Calculator
Professional reference with clinical context for using CDAI in Crohn's disease management.
Merck Manual📚 Clinical Context & Guidelines
Best et al. (1976)
Original development of CDAI at Midwest Regional Health Center - remains gold standard for clinical trials
Clinical Response Definition
Response = CDAI decrease ≥70 points; Significant response = decrease ≥100 points; Remission = CDAI <150
Modern Alternatives
Harvey-Bradshaw Index (simpler), SES-CD (endoscopic), PRO-2 (patient-reported) - CDAI still required for many drug trials
Treatment Targets (STRIDE-II Guidelines)
Aim for clinical remission (CDAI <150) PLUS objective improvement (CRP normalization, fecal calprotectin <250, endoscopic healing)
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