Anti-tubercular therapy given to differentiate Crohn's disease from intestinal tuberculosis predisposes to stricture formation

Treatment trial with anti-tubercular therapy (ATT) is a common strategy in tuberculosis-endemic countries in case of a diagnostic dilemma between intestinal tuberculosis and Crohn's disease (CD). Our aim was to determine the long-term clinical course of patients who received ATT before an eventual diagnosis of CD was made. We performed retrospective-comparison between CD patients who received ≥6 months of ATT vs those who did not receive ATT. Outcomes assessed were change in disease behavior during follow-up, requirement of surgery and medication use. 760 patients with CD were screened for the study and after propensity matching for location and behavior of disease, 79 patients in each group were compared. Progression from inflammatory (B1) to stricturing/fistulizing (B2/B3) phenotype was more among CD patients who received ATT (B1, B2, B3 - 73.4%, 26.6%, 0% at baseline vs. 41.8%, 51.9%, 6.3% at follow-up) as compared to those who did not receive ATT (B1, B2, B3 - 73.4%, 26.6%, 0% at baseline vs. 72.2%, 27.8%, 0% at follow-up) with an odds ratio of 11.05(3.17 - 38.56). The usage of 5-ASA, steroids, immunosuppressants, anti-TNFs was similar between both the groups. On survival analysis, CD patients who received ATT had a lower probability of remaining free of surgery (45%) than those who did not (76%) at 14 years of follow-up, HR=3.22(95% CI, 1.46-7.12, p=0.004). Crohn's disease patients diagnosed after a trial with anti-tubercular therapy had an unfavorable long-term disease course with higher rate of stricture formation and less chances of remaining free of surgery.