The paediatric Crohn’s disease morbidity index (PCD-MI); development of a tool to assess long-term disease burden using a data driven approach

Background/Objective– Heterogeneity and chronicity of Crohn’s disease (CD) make prediction of outcomes difficult. To date, no longitudinal measure can quantify burden over a patient’s disease course, preventing assessment and integration into predictive modelling. Here, we aimed to demonstrate the feasibility of constructing a data driven, longitudinal disease burden score.Methods– Literature was reviewed for tools used in assessment of CD activity. Themes were identified to construct a paediatric CD morbidity index (PCD-MI). Scores were assigned to variables. Data were extracted automatically from the electronic patient records at Southampton Children’s Hospital, diagnosed from 2012 to 2019 (inclusive). PCD-MI scores were calculated, adjusted for duration of follow up and assessed for variation (ANOVA) and distribution (Kolmogorov-Smirnov).Results– Nineteen clinical/biological features across five themes were included in the PCD-MI including blood/faecal/radiological/endoscopic results, medication usage, surgery, growth parameters and extraintestinal manifestations. Maximal score was 100 after accounting for follow-up duration.PCD-MI was assessed in 66 patients, mean age 12.5 years. Following quality filtering, 9528 blood/faecal test results and 1309 growth measures were included. Mean PCD-MI score was 14.95 (range 2.2-32.5), data were normally distributed (p=0.2) with 25% of patients having a PCD-MI Conclusions– PCD-MI is a calculatable measure for a cohort of patients diagnosed over an 8-year period, integrating a wide-range of data with potential to determine high or low disease burden. Future iterations of the PCD-MI require refinement of included features, optimised scores and validation on external cohorts.