Influence of methotrexate on gastrointestinal symptoms in patients with rheumatoid arthritis

AIM: This study aimed to determine the influence of methotrexate (MTX) on gastrointestinal (GI) symptoms in patients with rheumatoid arthritis (RA). METHODS: This cross-sectional study examined 529 consecutive patients with RA receiving oral MTX in our department between April 1 and September 30, 2017. GI symptoms were evaluated by the Gastrointestinal Symptom Rating Scale (GSRS); a score of ≥2 was considered "symptomatic." Prevalence of GI symptoms was compared between patients receiving ≤8 mg/wk (low-dose) vs >8 mg/wk (high-dose) of MTX. RESULTS: Of our study population, 313 (59%) received low-dose MTX at a median (interquartile range) dose of 6 (6-8) mg/wk, whereas 216 (41%) received high-dose MTX at a median dose of 12 (10-12) mg/wk. Relative to the low-dose MTX group, the high-dose MTX group exhibited a higher prevalence of reflux (32% vs 24%, P = 0.043) and abdominal pain (28% vs 18%, P = 0.007). There was no significant group-dependent difference in the prevalence of indigestion, diarrhea or constipation. Multivariate logistic regression analysis revealed that high-dose MTX (>8 mg/wk) was independently associated with reflux (odds ratio [OR]: 1.62, 95% confidence interval [CI]: 1.07-2.43) and abdominal pain (OR: 1.60, 95% CI: 1.04-2.43), and that the ORs for reflux and abdominal pain among those receiving high-dose MTX (>8 mg/wk) were similar to those using nonsteroidal anti-inflammatory drugs. CONCLUSION: High-dose MTX is independently associated with the prevalence of upper GI symptoms in Japanese patients with RA.