Risks of malignant lymphoma in rheumatoid arthritis patients receiving methotrexate-alone and in combination therapy compared with the general population: A study based on a Japanese medical claims database.

Objective: The risk of malignancy in patients with rheumatoid arthritis (RA) treated with methotrexate (MTX) and biological disease-modifying antirheumatic drug (bDMARD) combination therapy is unknown. This study aimed to clarify the incidence of malignancy and the recommended monitoring period in patients receiving this combination therapy.

Materials And Methods: A retrospective, observational study based on a large Japanese medical claims database was conducted between April 2013 and February 2020.