To determine the risk of adverse events in rheumatoid arthritis (RA) patients treated with biological disease-modifying anti-rheumatic drugs (bDMARD) versus traditional DMARDs (tDMARD).
This retrospective study used Taiwan's National Health Insurance Research Database to capture data for adult patients diagnosed with RA between 1 January 1999 and 31 December 2009 and treated with tDMARD or bDMARD. The endpoints were patients with cases of an inpatient serious bacterial infection (SBI), diagnosis of tuberculosis (TB) or lymphoma. Within the bDMARD cohort, individual bDMARDS with adequate data were also compared (adalimumab and etanercept). Propensity-score matching was used to adjust for significant (P ≤ 0.05) patient characteristics. Incidence rate ratios (IRR) of SBI/TB/lymphoma cases versus non-cases were adjusted for exposure time (rate per 100,000 patient-years) and 95% confidence intervals were constructed to assess whether IRRs differed from 1.0.
Of 34,947 potential patients, 7888 tDMARD, 3459 bDMARD (including 1492 etanercept and 746 adalimumab) patients were matched for analysis. A total of 2150 cases were identified and of these 1711 were SBI, 406 as TB and 33 as lymphoma. For all cases except SBI, the IRR (95% CI) was higher for bDMARD versus tDMARD (SBI 1.04 [0.89-1.19]; TB 2.67 [2.12-3.34]; lymphoma 3.24 [1.37-7.06]). Excepting lymphoma, IRR was higher for adalimumab versus etanercept (SBI 1.83 [1.19-2.77]; TB 2.35 [1.29-4.15]; lymphoma 1.49 [0.03-18.66]).
There was a higher risk for specified infections and lymphoma with bDMARD versus tDMARD and adalimumab versus etanercept.