Assessing disease activity using the pediatric Crohn’s disease activity index: Can we use subjective or objective parameters alone?

BACKGROUND: The pediatric Crohn's disease activity index (PCDAI) is used as a standard tool to assess disease activity in clinical trials for pediatric Crohn's disease. AIM: To examine which items on the PCDAI drive assessment of disease activity, and how subgroups of subjective and objective items reflect change in disease state over time. METHODS: = 474). Change in individual PCDAI scores from baseline to Q1 and to Q4 were examined using the non-weighted PCDAI. RESULTS: < 0.05). Subjective and objective subgroups of items predicted less variance (18% and 22%) on total PCDAI scores at Q1 and Q4 compared to the full PCDAI, or a composite scale (both 32%) containing significant predictors. CONCLUSION: Although subjective items on the PCDAI change the most over time, the full PCDAI or a smaller composite of items including a combination of subjective and objective components classifies disease activity better than a subgroup of either subjective or objective items alone. Reliance on subjective or objective items as stand-alone proxies for disease activity measurement could result in misclassification of disease state.