Background/Purpose: Treatment of rheumatoid arthritis
(RA) with disease modifying anti-rheumatic drugs (DMARDs) has undergone major
advances in last two decades. More than 10 non-biologic DMARDs and 9 biologic
DMARDs are currently approved in the United States for the indication of RA.
Yet, little is known about the population level time-trends in use of these
agents. Therefore, we described secular trends in use of DMARDs for initial and
subsequent treatment of RA in publicly and privately insured patients.

Methods: Claims data derived from private (United
HealthCare, 2004-2013) or public (Medicaid Analytic eXtract (MAX), 2000-2010)
insurance programs were used to conduct a retrospective cohort study. RA
patients were identified from either data source based on at least two medical
claims with ICD-9 code of 714.xx and classified into three groups by their
DMARD use in a 12-month baseline period: 1) DMARD-naïve patients, 2) biologic-naïve
patients, or 3) biologic-exposed patients. In a 12-month follow-up period, we
identified initiation of the first ever DMARD among DMARD-naïve patients,
initiation of the first ever biologic agent among biologic-naïve patients, and
initiation of a second or later biologic agent among biologic-exposed patients.
Among the patients initiating the new DMARD of interest during follow-up in
each group, we calculated the proportion of patients initiating individual
DMARDs for all available calendar years and reported time-trends.

Results: A total of 75,545 RA patients with private
and 95,624 with public insurance were identified as eligible for this study.
Mean age (SD) the cohort was 48 (12) years and 78% of the patients in the
cohort were female. Among DMARD-naïve RA patients, methotrexate (42%),
hydroxychloroquine (32%), and sulfasalazine (9%) were the three most commonly
used agents as the first-ever DMARD during our study period. Among
biologic-naïve patients, etanercept (45%) was the most commonly initiated agent
as the first-ever biologic, followed by adalimumab (25%) and infliximab (20%).
A decreasing trend for infliximab was observed between 2001 and 2012 as the
first ever biologic agent; while newer agents, abatacept and certolizumab,
showed increasing trend in use since their introduction (p<0.05) (Figure 1).
Among biologic-exposed patients, a decreasing trend in the use of adalimumab and
infliximab, while an increasing trend for abatacept, golimumab, and
certolizumab as the second-line biologic of choice was noted since their
introduction (p<0.05 for all trends).   

Conclusion: Use of etanercept as the most common
first-line agent has remained relatively stable over the past decade; however,
use of adalimumab and infliximab is decreasing and the use of newer biologics,
especially abatacept, golimumab, and certolizumab, is increasing as both
first-line and second-line agents in recent years.