O-005 Feasibility and Validity of the Pediatric Ulcerative Colitis Activity Index in Real-world Clinical Practice

Abstract

BACKGROUND: The Pediatric Ulcerative Colitis Activity Index (PUCAI) is a noninvasive disease activity index developed as a clinical trial endpoint. More recently, practice guidelines have recommended the use of PUCAI in clinical care, including PUCAI-based treatment algorithms. Although the use of PUCAI has been evaluated in single-center and small multi-center research studies, little is known about the feasibility and performance of PUCAI when used in routine clinical practice. We therefore sought to evaluate the feasibility, validity and the responsiveness to change of PUCAI in a large, diverse collection of clinical practices. METHOD(S): ImproveCareNow (ICN) is a multicenter quality improvement network focusing on pediatric inflammatory bowel disease. This registry contains disease and treatment data collected prospectively and longitudinally during outpatient encounters. We extracted data from the 2 most recent encounters for all patients with ulcerative colitis in the ICN registry (September 2006 to December 2012). Feasibility was determined by the percent of patients for whom all PUCAI components were recorded at the most recent visit. To assess validity, we first evaluated the distribution of PUCAI scores across categories of the Physician Global Assessment (PGA) using box and whisker plots, and comparing differences using the Kruskal-Wallis test. The association between PUCAI and PGA was also measured using Pearson's correlation coefficient, percentage of agreement, and Cohen's Kappa coefficients (unweighted and weighted). We next evaluated the distribution of DELTAPUCAI according to DELTA PGA using box and whisker plots, and tested for differences using the Kruskal-Wallis test. We then evaluated test-retest reliability between the 2 most recent visits in patients whose disease activity by PGA remained unchanged using the ANOVA-based intra-class correlation coefficient (ICC). To evaluate responsiveness to change among patients with a difference in disease activity between the last 2 visits, we calculated Guyatt's responsiveness statistic with the minimal important difference (MID), and evaluated the association between DELTAPUCAI and DELTA PGA using Pearson's correlation coefficient. RESULT(S): 2503 pediatric patients with ulcerative colitis were included (49.5{\%} males, mean age 15.2 +/- 4.1 years, mean disease duration 3.7 +/- 3.2 years). PUCAI had very high feasibility: 96{\%} of visits contained all 6 required components. PUCAI demonstrated excellent discriminatory ability between remission, mild and moderate disease based on PGA; discrimination between moderate and severe disease was less robust (Fig. 1). There was good correlation with PGA (r = 0.76 [P {\textless} 0.001], percentage of agreement 0.77, Cohen's unweighted kappa statistic k = 0.53 [P {\textless} 0.001] and weighted kappa k = 0.73 [P {\textless} 0.001]). The test-retest reliability of the PUCAI was also good (ICC = 0.72 [95{\%} CI 0.70-0.75], P {\textless} 0.001). The responsiveness statistic was 1.18 and the correlation of DELTAPUCAI with DELTA PGA was 0.69 (P {\textless} 0.001). The DELTAPUCAI differentiated well into the different DELTA PGA categories (P {\textless} 0.001) (Fig. 2). CONCLUSION(S): Based on this large-scale, multicenter evaluation of the PUCAI in a simulated routine clinical practice setting, we conclude that PUCAI is highly feasible, valid, and responsive to change. These findings support the use of PUCAI as a clinical tool, as well as a research tool.