Objectives: 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 routine clinical care. We therefore sought to evaluate the feasibility, validity, and responsiveness of PUCAI in a large, diverse collection of pediatric gastroenterology practices.
Methods: We extracted data from the 2 most recent encounters for patients with ulcerative colitis in the ImproveCareNow registry. Feasibility was determined by the percentage of patients for whom all PUCAI components were recorded, validity by correlation of PUCAI scores across physician global assessment (PGA) categories, and responsiveness to change by the correlation between the change in PUCAI and PGA scores between visits.
Results: A total of 2503 patients were included (49.5% boys, age 15.2 ± 4.1 years, disease duration 3.7 ± 3.2 years). All items in the PUCAI were completed for 96% of visits. PUCAI demonstrated excellent discriminatory ability between remission, mild, and moderate disease; discrimination between moderate and severe disease was less robust. There was good correlation with PGA (r = 0.76 [P < 0.001] and weighted kappa κ = 0.73 [P < 0.001]). The PUCAI change scores correlated well with PGA change scores (P < 0.001). Test-retest reliability of the PUCAI was good (intraclass correlation coefficient 0.72 [95% confidence interval 0.70-0.75], P < 0.001). Guyatt responsiveness statistic was 1.18, and the correlation of ΔPUCAI with ΔPGA was 0.69 (P < 0.001).
Conclusions: The PUCAI is feasible to use in routine clinical settings. Evidence of its validity and responsiveness supports its use as a clinical tool for monitoring disease activity for patients with ulcerative colitis.