Mo1278 Different Patterns of Diagnostic Testing Impact on the Phenotype of Crohn's Disease in Childhood

Abstract

Background: Previous studies have shown that diagnosis of Crohn's disease (CD) in childhood is associated with a different phenotype when compared to adults (higher risk for involvement of the upper gastrointestinal tract (UGI), ileocolonic disease (L3) and fibrostenotic behavior (B2). These studies did not factor in the differing pattern of diagnostic testing between the patient populations (types of imaging tests as well as number). We hypothesized that this may account at least partly for the difference in phenotype among the age-groups. Methods: A comprehensive medical chart review was done for 571 CD patients that were followed in a tertiary referral IBD clinic. The diagnosis and preliminary diagnostic workup for the majority of patients were done by referring community gastroenterologists and surgeons. Among the parameters that were recorded for each patient at specific time intervals were the type and number of imaging studies as well as parameters of disease phenotype according to the Montreal Classification (A1 diagnosed ,16, A2 diagnosed 16-40, A3 diagnosed .40). Results: The study included 452 patients that had complete data in the charts. Within one year of diagnosis, burden of disease was highest in A1 than A2 and A3 cohorts with greater proportion having upper GI involvement in A1 (19.3%) vs. A2 (11.1%, p=0.03) and vs A3 (2.6%, p,0.05) and of ileocolonic disease in A1 (42.5%) vs A2 (22.7%, p,0.01) and vs A3 (19.2%, p,0.01). These differences though were partly accounted for by the diagnostic testing undertaken within the first year of disease. The proportion of patients that had at least one imaging study that could identify UGI tract disease (upper endoscopy or small bowel barium study or CT/MRI scan) was greater in the A1 group (86.3%) vs. A2 (62.7%, p,0.01) and A3 groups (63.6%, p,0.01); and the proportion that had at least one relevant imaging study that could include the colon and ileum (colonoscopy or small bowel barium study or CT/MRI) was increased in A1 (95.5%) vs A2 (86.4%, p,0.05) but not vs A3 (88.3% =0.15). Despite more extensive imaging complicated disease behavior was less prevalent when CD was diagnosed in childhood. B1 (inflammatory) behavior was significantly higher among A1 (93.1%) vs A2 (85.2%, p ,0.05), and vs A3 (78.7%, p,0.01). Conclusions: Studying the phenotype of CD among different cohorts has to take into consideration the differing patterns of diagnostic imaging investigations within these cohorts. While it has been considered that children diagnosed with CD, particularly at a young age (A1) have a greater burden of and more aggressive disease; our data show that these children get more extensive investigations than adults which may enhance extent of disease found and yet does not lead to them being diagnosed with more complicated disease.