Does Adherence to RA Therapy Vary By Specific Drug Combinations?

U.S. Veterans with rheumatoid arthritis (RA) were significantly more likely to be adherent to a tumor necrosis factor inhibitor (TNFi) plus methotrexate combination therapy than to triple therapy with non-biologic disease-modifying antirheumatic drugs (DMARDs), a study published in Arthritis Care & Research found. 

Brian C. Sauer, PhD, of the Veterans Affairs Medical Center Salt Lake IDEAS Center, Salt Lake City, UT, and colleagues set out to compare the persistence and adherence to triple therapy with non-biologic DMARDs, methotrexate, hydroxychloroquine, and sulfasalazine, vs. a TNFi plus methotrexate in patients with RA. 

The team evaluated administrative and laboratory data for U.S. veterans with RA starting triple therapy or TNFi + methotrexate between January 2006 and December 2012. 

Treatment persistence was measured by 3 definitions: 1) no gap in therapy of ≥90 days for any drug in the original combination, 2) no added or switched DMARD and no decrease to non-biologic DMARD monotherapy, and 3) similar to second definition with allowance of a switch to another agent in the same drug class. Adherence was the proportion of days covered of ≥80%. 

In the analysis (n=4364), patients in the TNFi + methotrexate group were significantly more likely than patients in the triple therapy group to meet all persistence criteria in Definition 1 (risk difference [RD]: 13.1%, 95% CI: 9.2%, 17.0%); Definition 2 (RD: 6.4%, 95% CI: 2.3%, 10.5%), and Definition 3 (RD: 9.5%, 95% CI: 5.5%, 13.6%). Patients in the TNFi + methotrexate group also showed higher adherence during the first year (RD: 7.2%, 95% CI: 3.8%, 10.5%).

The researchers theorize that lower adherence rates in patients receiving triple therapy may be influenced by complexity of multiday dosing.

Summary and Clinical Applicability

Among U.S. Veterans with RA, adherence rates were improved with TNFi plus methotrexate combination therapy as compared to triple therapy with non-biologic DMARDs.

Reference

This article originally appeared on MPR