From the Guidelines
The Crohn's Disease Activity Index (CDAI) is the most widely used and recommended scoring system for assessing Crohn's disease severity, despite its limitations, as it is the most frequently used index for clinical trials and provides a comprehensive evaluation of disease activity 1.
Overview of Scoring Systems
The CDAI evaluates eight variables: number of liquid stools, abdominal pain severity, general well-being, presence of complications, use of antidiarrheal medications, presence of abdominal masses, hematocrit level, and body weight. Each variable is weighted differently, with scores ranging from 0 to 600. A score below 150 indicates remission, 150-220 suggests mild disease, 220-450 represents moderate disease, and above 450 indicates severe disease.
Comparison with Other Scoring Systems
Other scoring systems include the Harvey-Bradshaw Index (HBI), which is simpler and requires only five clinical parameters without laboratory values, and is subject to the same limitations as the CDAI in that the majority of the score is symptom-based 1. The HBI offers a simplified disease activity score, with a clinical response defined as a reduction from baseline of 3 points or more and remission as a score of <5.
Limitations and Future Directions
The CDAI correlates poorly with scores of endoscopic disease severity and with fecal and serum biomarkers of inflammation, and the US Food and Drug Administration (FDA) has indicated that the CDAI will no longer be acceptable as a measure of disease activity in clinical trials because it was not created according to FDA guidance for patient-reported outcomes (PROs) 1. The International Organization for the Study of Inflammatory Bowel Diseases (IOIBD) is in the midst of designing an overall disease severity index that is based on impact of the disease on the patient, objective measures of inflammatory burden, and disease course.
Clinical Application
These scoring systems help clinicians monitor disease activity, guide treatment decisions, and evaluate response to therapy. Regular assessment using these tools allows for timely adjustments in treatment plans to achieve and maintain disease remission. The CDAI is heavily weighted toward symptoms, with a clinical response defined as a reduction from baseline of 70–100 points or more and clinical remission as a score of <150 1.
From the FDA Drug Label
The median Pediatric Crohn's Disease Activity Index (PCDAI) was 40 (on a scale of 0 to 100). Clinical response was defined as a decrease from baseline in the PCDAI score of ≥ 15 points and total PCDAI score of ≤ 30 points. Clinical remission was defined as a PCDAI score of ≤ 10 points.
The scoring system for Crohn's disease is the Pediatric Crohn's Disease Activity Index (PCDAI), which ranges from 0 to 100.
- Clinical response is defined as a decrease from baseline in the PCDAI score of ≥ 15 points and total PCDAI score of ≤ 30 points.
- Clinical remission is defined as a PCDAI score of ≤ 10 points 2 2.
From the Research
Scoring Systems for Crohn's Disease
- The Crohn's Disease Activity Index (CDAI) is a widely used scoring system to measure Crohn's disease activity 3.
- The CDAI has been used for over a quarter of a century and its reliability and validity have been examined 3.
- Other scoring systems, such as the Harvey-Bradshaw Index, the Cape Town Index, and a three-variable version of the CDAI, have also been developed to assess Crohn's disease activity 3.
- The Inflammatory Bowel Disease Questionnaire (IBDQ) is another instrument used to assess Crohn's disease, which evaluates patients in the domains of bowel, systemic, emotional, and social function 3.
Clinical Indices and Quality of Life Scores
- Clinical indices, such as the CDAI, Perianal Disease Activity Index (PDAI), and fistula drainage assessment, are used to measure Crohn's disease activity 4.
- Quality of life scores, such as the IBDQ, are used to assess the impact of Crohn's disease on patients' daily lives 4.
- Sub-clinical markers, such as C-reactive protein, faecal calprotectin, and intestinal permeability, can also be used to monitor disease activity 4.
Endoscopic Indices
- Endoscopic indices, such as the Crohn's Disease Endoscopic Index of Severity (CDEIS) and the Simple Endoscopic Score for Crohn's Disease (SES-CD), are used to assess the severity of Crohn's disease 4.
- Rutgeeerts' score is used to assess postsurgical recurrence of Crohn's disease 4.
- These scoring systems have advantages and disadvantages, and their use is often limited to clinical trials due to their complexity and time-consuming nature 4.
Treatment and Remission
- The treatment of mild to moderate Crohn's disease can be guided by the CDAI score, with higher scores indicating more severe disease 5, 6.
- Inducing remission in Crohn's disease can be achieved with various treatments, including budesonide, sulfasalazine, corticosteroids, and mesalamine 5, 6, 7.
- The choice of treatment depends on the severity of the disease, the location of the disease, and the patient's response to previous treatments 5, 6.