The effect of smoking on response to methotrexate in rheumatoid arthritis patients: A systematic review and meta-analysis.

We searched PubMed, Embase, and Web of Science until 6 June 2022. Observational or interventional studies investigating MTX-IR in RA patients based on smoking status were included. Two independent reviewers assessed the risk of bias and the certainty of the evidence using ROBINS-I and grades of recommendation, assessment, development, and evaluation (GRADE) tools, respectively.