Factors associated with early outcomes following standardised therapy in children with ulcerative colitis (PROTECT): a multicentre inception cohort study

Previous retrospective studies of paediatric ulcerative colitis have had limited ability to describe disease progression and identify predictors of treatment response. In this study, we aimed to identify characteristics associated with outcomes following standardised therapy after initial diagnosis. The PROTECT multicentre inception cohort study was based at 29 centres in the USA and Canada and included paediatric patients aged 4–17 years who were newly diagnosed with ulcerative colitis. Guided by the Pediatric Ulcerative Colitis Activity Index (PUCAI), patients received initial standardised treatment with mesalazine (PUCAI 10–30) oral corticosteroids (PUCAI 35–60), or intravenous corticosteroids (PUCAI ≥65). The key outcomes for this analysis were week 12 corticosteroid-free remission, defined as PUCAI less than 10 and taking only mesalazine, and treatment escalation during the 12 study weeks to anti-tumour necrosis factor α (TNFα) agents, immunomodulators, or colectomy among those initially treated with intravenous corticosteroids. We identified independent predictors of outcome through multivariable logistic regression using a per-protocol approach. This study is registered with ClinicalTrials.gov, number NCT01536535. Patients were recruited between July 10, 2012, and April 21, 2015. 428 children initiated mesalazine (n=136), oral corticosteroids (n=144), or intravenous corticosteroids (n=148). Initial mean PUCAI was 31·1 (SD 13·3) in children initiating with mesalazine, 50·4 (13·8) in those initiating oral corticosteroids, and 66·9 (13·7) in those initiating intravenous corticosteroids (p