Little is known about the transition from nonbiologic disease-modifying antirheumatic
drugs (DMARDs) to biologic DMARDs or about individual nonbiologic DMARD use patterns
among patients with rheumatoid arthritis (RA). This study examined time to initiation
of biologic DMARDs and nonbiologic DMARD medication adherence and persistence among
Texas Medicaid recipients with RA taking nonbiologic DMARDs.
In this retrospective study (July 1, 2003–December 31, 2010) of the Texas Medicaid
database, patients were aged 18 to 62 years at index, were diagnosed with RA (International Classification of Diseases, Ninth Revision, Clinical Modification, code 714.xx), had no claims for nonbiologic or biologic DMARDs in the preindex period,
and had a minimum of 2 prescription claims for the same nonbiologic DMARD in the postindex
period. Kaplan-Meier survival analysis and log-rank tests were used to compare time
to initiation of biologic DMARDs according to nonbiologic DMARD type and therapy.
Adherence and persistence were examined according to nonbiologic type and therapy
by using ANOVA models and χ2, Duncan, and t tests.
On average, patients were 47.9 (±10.4) years of age, mostly female (89.1%) and Hispanic
(55.2%). Methotrexate (MTX) and leflunomide (LEF) users took the shortest time to
initiate biologic DMARDs (207  days and 188  days, respectively). LEF users
had the highest mean adherence of 37.5% (27.5%), which was similar to MTX users (35.7%
[26.9%]), whereas dual-therapy users had the lowest mean adherence at 17.1% (14.4%).
Sulfasalazine users (108  days) had the lowest persistence, whereas LEF (227
 days) and MTX (211  days) users had the longest persistence. Nonbiologic
DMARD monotherapy users were more adherent than dual-therapy users (32.6% [25.8%]
vs 17.1% [14.4%]).
These results should be interpreted in light of some study limitations, such as using
proportion of days covered as a proxy for adherence, not having clinical data to control
for RA severity, and lack of generalizability to all US populations. Given the study
findings, both clinicians and other decision makers may want to investigate the potential
driving factors of initiation of biologic DMARDs to provide effective RA management
and consider patient education programs to enhance medication adherence and persistence
to RA medications.