Background/Purpose: The linkage of pharmacy databases with objective clinical outcome measures provides an opportunity to compare the effectiveness and safety of rheumatoid arthritis (RA) therapies in real world clinical settings. Merging information from the Veterans Affairs RA (VARA) registry initiated in 2003 with assessment of disease activity and the VA Pharmacy Benefits Management (PBM) database with data from 1998 allows comparison of patients receiving combination therapy with methotrexate, sulfasalazine and hydroxychloroquine (MTX/SH) to patients receiving the combination of methotrexate and anti-tumor necrosis factor (TNF) therapy (MTX/TNF).
Methods: VARA routinely collects disease activity score (DAS28) on RA patients in this longitudinal prospective observational cohort study. For each prescription, PBM data was used to ascertain duration of the prescription, total dose dispensed, and anticipated date for refill of medication was recorded. Individual prescription courses were consolidated to determine regimens of combination therapy with MTX/SH and MTX/TNF. Regimens were defined as time from the initiation of the combination therapy regimen until the expected refill date for the last treatment before a 90 day gap or discontinuation. The average DAS28 and average ESR during each regimen of greater than 90 days was calculated during the observation period from 90 days after initial prescription to the end of the regimen.
Results: Of the 1382 patients in the VARA cohort, 443 (32%) received combination therapy with either MTX/SH or MTX/TNF; approximately half of these (n = 259) receiving treatment during observation. Of these 443 combination treated patients, 131 (30%) received only MTX/SH, 254 (57%) received only MTX/TNF and 58 (13%) received both combinations. A comparison of patients receiving only MTX/SH to MTX/TNF showed that patient treated with only MTX/SH were more frequently men and older than patients receiving only MTX/TNF. Among those with available DAS28 during VARA observation, measures of disease activity were similar across treatment groups (Table).
Conclusions: Among U.S. veterans with RA, approximately half have received combination therapies with MTX/SH and/or MTX/TNF. In patients receiving these treatments, the combination of non-biologic DMARDs appears to be used more commonly than MTX/TNF in men and among older individuals. These differences may be related to channeling bias that could not be detected by the analysis for confounders. In this observational study, these treatment combinations do not appear to result in meaningful differences in disease activity over follow-up.
Disclosure: G. W. Cannon, None; B. C. Sauer, None; C. L. Hayden, None; S. G. Pickard, None; G. S. Kerr, None; J. S. Richards, Pfizer Inc, 2 ; D. S. Johnson, None; L. Caplan, None; T. R. Mikuls, None; A. M. Reimold, None.