Low-dose azathioprine effectively improves mucosal healing in Chinese patients with small bowel Crohn's disease

OBJECTIVE To evaluate mucosal healing after 24-month low-dose azathioprine (AZA) treatment in Chinese patients with moderate small bowel Crohn's disease (CD). METHODS Patients with lesions mainly located at the ileum were screened by baseline multislice computed tomography enterography and anal-route double-balloon enteroscopy (DBE). They were naive to any immunomodulators and biological agents before the enrollment. Lesions from 150 cm of the terminal ileum proximal to ileocecal valve were assessed by DBE with the simple endoscopic score for CD (SES-CD) after 12 and 24 months of low-dose AZA treatment, respectively. RESULTS The average maximal tolerance dose of AZA was 61.8 ± 17.2 mg/day. The total rates of complete, near-complete, partial and no mucosal healing in 36 patients were 19.4%, 5.6%, 27.8% and 47.2% at month 12 and 30.6%, 25.0%, 33.3% and 11.1% at month 24, respectively. The baseline SES-CD (odds ratio [OR] 2.71, 95% confidence interval [CI] 1.11-6.63, P = 0.029) and duration of disease (OR 1.27, 95% CI 1.10-1.47, P = 0.001) were two relevant factors associated with the mucosal healing of patients with small bowel CD. CONCLUSION A 24-month low-dose AZA regimen as maintenance treatment in moderate small bowel CD could achieve a higher mucosal healing rate than that of 12-month treatment in Chinese patients, especially in those with duration of disease less than 12 months and a baseline SES-CD of 5 or 6.