A short pediatric Crohnʼs Disease Activity Index for Quality Improvement and Observational Research

Practical and objective instruments to assess disease activity during routine clinical encounters are needed for quality improvement (QI) and observational research in pediatric Crohn's disease (CD). The Pediatric Crohn's Disease Activity Index (PCDAI) and the Abbreviated PCDAI (APCDAI) require laboratory testing and/or perirectal examination, and therefore may be difficult to complete at each clinic visit. 1) To determine the proportion of routine clinic visits during which the PCDAI and APCDAI were fully completed, and to identify the elements of these indices that were the most difficult to complete; 2) To create a shorter, more practical index by retaining and re-weighting the most feasible and informative components. Physicians in the ImproveCareNow Collaborative for pediatric inflammatory bowel diseases (IBD) were asked to record each component of the PCDAI and to assign a Physician Global Assessment (PGA) of disease severity at each patient visit. We first determined the proportion of CD visits during which each index component, and total PCDAI and APCDAI scores, could be assessed. We then created a Short PCDAI by retaining all individual components completed in at least 80% of visits. Finally, we used linear regression and clustered correlation to assign a weight to each component to optimize the association between the Short PCDAI and the PCDAI. The performance of the Short PCDAI was evaluated using standard descriptive statistics. 1123 subjects comprising 3643 visits were included in this analysis. The PCDAI could be scored in 709 visits (19.5%), and the APCDAI could be scored in 1733 visits (47.6%). After eliminating laboratory tests and the requirement for perirectal examination, the Short PCDAI, which includes general well-being, abdominal pain, stools, weight, abdominal exam, and extra-intestinal manifestations, could be scored in 2413 (66.2%) of visits. The Short PCDAI was highly correlated with the PCDAI (r= 0.86) and also positively associated with disease severity assessed by PGA. Short PCDAI scores (0-80 scale) for patients with inactive, mild, moderate, and severe disease were 5.1 (7.5), 15 (10.9), 26 (14.5), and 37.6 (14.5), respectively (mean score, +/- SD). Existing instruments to assess disease activity in pediatric CD are difficult to complete in the context of routine clinical care. The Short PCDAI is a practical and valid tool to measure disease activity in the clinical setting. Use of this instrument should facilitate QI and observational research in pediatric CD.