Revised algorithmic approach to differentiate between non-specific and specific etiologies of chronic terminal Ileitis.

Abstract

/Aims-Chronic isolated terminal ileitis(TI) may be seen in Crohn's disease(CD) and Intestinal tuberculosis(ITB) in addition to other etiologies that may be managed symptomatically. We developed a revised algorithm to distinguish patients with a specific etiology from a non specific etiology. Patients with chronic isolated TI following-up from 2007 to 2022 were retrospectively reviewed. A specific(ITB or CD) diagnosis was made based on standardized criteria and other relevant data was collected. Using this cohort, validation of a previously suggested algorithm was conducted. Further, based on the results of a univariate analysis, a multivariate analysis with bootstrap validation was used to develop a revised algorithm. We included 153 patients(mean age-36.9+14.6 years, males-70%, median duration-1.5 years, range:0-56 years) with chronic isolated TI of whom 109(71.2%) received a specific diagnosis(CD-69, ITB-40). On multivariate regression and validation statistics with a combination of clinical, laboratory, radiological and colonoscopic findings, an optimism corrected c-statistic of 0.975 and 0.958 was obtained with and without histopathological findings respectively. Revised algorithm, based on these, showed a sensitivity, specificity, positive and negative predictive value, and overall accuracy of 98.2%(95%CI:93.5 - 99.8), 75.0%(95%CI:59.7 - 86.8), 90.7%(95%CI:85.4 - 94.2), 94.3%(95%CI:80.5 - 98.5) and 91.5%(95%CI:85.9 - 95.4), respectively. This was more sensitive and specific than the previous algorithm(accuracy 83.9%, sensitivity 95.5%, and specificity 54.6%). We developed a revised algorithm and a multi-modality approach to stratify patients with chronic isolated TI into specific and non-specific etiologies with an excellent diagnostic accuracy which could potentially avoid missed diagnosis and unnecessary side effects of treatment.