BACKGROUND Methotrexate monotherapy is recommended as a maintenance therapy for Crohn's disease (CD). However, long-term follow-up data are scarce.

OBJECTIVES We aimed to examine the effectiveness and tolerability of methotrexate monotherapy in 94 CD patients from three inflammatory bowel disease Clinics in Korea.

DESIGN This was a multicenter retrospective observational study.

METHODS Patients with active CD treated with methotrexate monotherapy were included. Clinical characteristics, laboratory indicators, endoscopy indices were evaluated at baseline, 6, 12, and 24 months. Independent factors associated with long-term clinical and endoscopic outcomes were determined.

RESULTS Methotrexate was administered orally (70.2%) or parenterally (29.8%). The mean methotrexate induction dose was 15.3 ± 0.4 mg/week, and the mean duration of therapy was 26.2 months. Of 76 patients who were treated for >6 months, the clinical remission rates were 76.3%, 74.6%, and 80.0% at 6, 12, and 24 months, respectively, by per-protocol analysis. The mean CRP levels were 7.5 ± 1.3, 5.3 ± 1.2, 3.8 ± 0.7, and 2.6 ± 0.5 mg/L at 0, 6, 12, and 24 months, respectively. Of 31 patients who underwent follow-up endoscopy after 27.5 months, the endoscopic remission rate was 38.7%. Baseline hemoglobin level <10 g/dL was a significant independent factor negatively associated with clinical remission at 6 [odds ratio (OR): 0.023, 95% confidence interval (CI): 0.003-0.206, p = 0.001] and 12 (OR: 0.079, 95% CI: 0.009-0.699, p = 0.023) months. Parenteral administration was a significant independent factor positively associated with clinical remission (OR: 11.231, 95% CI: 1.027-122.811, p = 0.047) and endoscopic remission (hazard ratio: 4.711, 95% CI: 1.398-15.874, p = 0.012) at 12 months.

CONCLUSIONS Methotrexate monotherapy was effective and tolerable as a maintenance therapy in CD patients.