Fig. 1

Definition of the cohort. Eligible patients were required to have two diagnoses of rheumatoid arthritis (RA) that were ≥7 days but <365 days apart, with continuous insurance coverage between one year prior to the first RA diagnosis (1 ^st RA) date and one year after the second RA diagnosis (2 ^nd RA) date. The second RA diagnosis date was defined as the index date, and the baseline period was defined as time between the second RA diagnosis and one year prior to the first RA diagnosis