Table 2.

Comparator cohorts.

Rheumatoid Arthritis Cohorts	Description	Hospitalized Infections	Malignancies
British Columbia, Canada, RA cohort¹⁸	Administrative data on physician visits, hospitalizations, and medications, collected between 1996 and 2001. N = 12,337 DMARD-treated patients	✓	✓
PharMetrics claims database¹⁹	A US integrated managed care database including data from pharmacy, provider, and facility claims for members enrolled in 61 health plans across the US from 1998 to 2002. N = 122,272 RA patients	✓
National Data Bank for Rheumatic Diseases, United States (NDB)²⁰	Longitudinal cohort reported on patient questionnaire between 1998 and 2003. N = 10,499 DMARD-treated patients		✓
General Practice Research Database, United Kingdom (GPRD)²¹	Electronic medical records between 1987 and 2001. N = 14,467 DMARD-treated patients		✓
US general population: Surveillance Epidemiology and End Results (SEER) database²²	The SEER Program of the national Cancer Institute provides information on cancer statistics from various locations and sources throughout the United States. Data here are based on SEER 17, collected 2000–2007. N = 79,021,933 participants		✓