Prevalence and Progression of Incidental Terminal Ileitis on Non-diagnostic Colonoscopy: A Systematic Review and Meta-analysis

Abstract

Background Incidentally-diagnosed terminal ileitis (IDTI) has been reported among asymptomatic persons undergoing non-diagnostic colonoscopy. The purpose of our study was to determine the prevalence and long-term outcomes of asymptomatic terminal ileitis. Methods We performed a systematic review using three biomedical databases (Medline, Embase and Web of Science) and relevant scientific meeting abstracts. We identified observational studies that reported the prevalence of IDTI in adults undergoing screening or polyp surveillance colonoscopy and/or the long-term outcomes of such lesions. A random-effects meta-analysis was conducted to determine the pooled prevalence rate of IDTI. The progression of IDTI to overt Crohn’s disease (CD) was also described. Results Of 2,388 eligible studies, 1,784 were screened after excluding duplicates, 84 were reviewed in full text, and 14 studies were eligible for inclusion. Seven studies reported the prevalence of IDTI in 44,398 persons undergoing non-diagnostic colonoscopy, six studies reported follow-up data, and one study reported both types of data. The pooled prevalence rate of IDTI was 1.6% (CI 0.1–21.8%) with significant heterogeneity (I 2 = 99.7). Among patients who had undergone non-diagnostic colonoscopy and had follow-up data (range 13–84 months reported in five studies), progression to overt CD was rare. Conclusion IDTI is not uncommon on non-diagnostic colonoscopies. Based on limited data, the rate of its progression to overt CD seems low, and watchful waiting is likely a reasonable strategy. Further long-term follow-up studies are needed to inform the natural history of incidental terminal ileitis, factors that predict progression to CD, and therapeutic implications.

Nonspecific ileitis: Impact of histopathology and gastrointestinal ultrasound in achieving the diagnosis of Crohn's disease

“…Overall, the prevalence of nonspecific ileitis in our cohort was low (0.5% of procedures). This prevalence rate is similar to that of nonspecific ileitis reported in a systematic review of patients undergoing ileocolonoscopy for bowel cancer screening and polyp surveillance 5 . However, it should be noted that this included all procedures at our institution including surveillance procedures for those with known inflammatory bowel disease.…”

“…This prevalence rate is similar to that of nonspecific ileitis reported in a systematic review of patients undergoing ileocolonoscopy for bowel cancer screening and polyp surveillance. 5 However, it should be noted that this included all procedures at our institution including surveillance procedures for those with known inflammatory bowel disease. Furthermore, with the way data were extracted, using a label of colonoscopy defined by the treating clinician, we were unable to determine the rate of complete colonoscopy to the cecum and ileal intubation in this cohort.…”

“…9 Furthermore, in the systematic review described above, eight studies had long-term follow-up data in 147 patients and the overall risk of progression from incidental terminal ileitis to Crohn's disease was very low, but the authors were not able to quantify the risk. 5 Finally, first-degree relatives of patients with Crohn's disease have a high risk of nonspecific ileitis or subclinical inflammation that does not progress over time. 10 On the contrary, the finding of nonspecific ileitis situation is prone to over-investigation.…”

“…Only 28% of these cases had a final diagnosis of a nonspecific cause, accounting for 1.7% of all procedures performed 4 . In a systematic review of patients undergoing colonoscopy for colorectal cancer screening or polyp surveillance, the pooled prevalence rate of incidentally diagnosed terminal ileitis was 1.6%, although there was significant heterogeneity, with studies reporting variable prevalence rates 5 . The pooled prevalence, when repeated without the outlier study that had an exceptionally high prevalence, was 0.7%.…”

Approach to the Management of Recently Diagnosed Inflammatory Bowel Disease Patients: A User’s Guide for Adult and Pediatric Gastroenterologists

“…10 At the other end of the spectrum, incidental terminal ileitis can be diagnosed in 1.6% of individuals undergoing nondiagnostic colonoscopy, with an uncertain but likely low rate of progression to overt CD. 11 With respect to UC, most patients have mild to moderate severity and 10%-15% of patients can experience a severe course. 12 In a population-based cohort study, proctosigmoid location of colitis occurred in 73% of patients; of these, disease extension occurred in 23% of patients at 7 years of follow-up and it was a marker of worse prognosis.…”