Brassard P, Lowe AM, Bernatsky S et al. Arthritis Rheum 2009;61:300–4.
Immunosuppressants used to treat rheumatoid arthritis (RA), notably disease-modifying antirheumatic drugs (DMARDs) and corticosteroids, may modulate the risk of Mycobacterium tuberculosis (TB) in patients with RA. The incidence rate of TB in an RA cohort from Quebec, Canada was quantified and compared with the general population rate. In addition, the extent of the risk of TB in patients with RA after exposure to non-biological DMARDs was assessed.
The cohort included in this study consisted of 24 282 patients with rheumatoid arthritis (RA) identified from the Quebec (Canada) provincial physician billing and hospitalization data-bases from 1980–2003. Of these patients, 70.1% of the subjects were women. The mean subject age (± standard deviation) at the time of cohort entry was 61.7±14.6 years, which means that the study data were based on an elderly RA population. All subjects with at least one occurrence of a diagnosis of RA during an inpatient or outpatient visit were included into the study. Cohort subjects were restricted to those who were dispensed at least one prescription for disease modifying antirheumatic drug (DMARD) therapy. Country of birth, ethnicity, socioeconomic status, and the history of recent contact with an individual with tuberculosis (TB) remained unconsidered.