The ImproveCareNow Registry: Prediction of different remission rates in pediatric ulcerative colitis

Identifying predictors of clinical remission in pediatric ulcerative colitis (UC) will impact the therapeutic approach. We aimed to predict time to first (TFR), corticosteroid-free (TCSFR, ≥3 months corticosteroid withdrawal), and sustained remission (TSR, ≥6 months).

This retrospective study analyzed de-identified prospectively collected data from 2383 patients enrolled in ImproveCareNow (2007-2023). We included UC patients under 18 years at diagnosis. Remission was defined as a Pediatric UC Activity Index (PUCAI; <10 points). The Statistical Package for the Social Sciences version 29 with multiple imputation for missing data was used for statistical analysis. Cox regression identified predictors at diagnosis/enrollment (T0) or first visit (T1) on the outcomes (n = 1785). This study received ethics committee approval (23135-ICN_UC).

Mean TFR was 177.7 days, predicted by disease extent (p > 0.05) at T0 and history of severe UC (hazard ratio [HR] = 1.142, p = 0.05) before inclusion. In patients not reaching remission at T1 (subgroup; n = 964), TFR was predicted by PUCAI (confounder; moderate HR = 0.867 or severe disease HR = 0.697, p < 0.1) at T1 and history of severe UC (HR = 1.292, p = 0.007) before T1 (mean 25 days SEM 0.7). Mean TCSFR was 569.6 days, predicted by PUCAI (only mild HR = 0.728 and moderate HR = 0.559, p < 0.001) and use of corticosteroids (HR = 0.668, p < 0.001) at T1 (mean 32 days SEM 0.9). Mean TSR was 631.0 days, predicted by PUCAI (only mild HR = 0.721 and moderate HR = 0.541, p < 0.001) and the use of oral aminosalicylates (HR = 0.793, p = 0.003) at T1 (mean 30 days SEM 0.7).

Several clinical parameters in early disease course predict remission with increasing PUCAI as useful negative predictor.