Predictors for Low Disease Activity and Remission in
Rheumatoid Arthritis Patients Treated with
Biological DMARDs
Pathawut Wacharapornin MD, PhD*,
Parawee Suwannalai MD, PhD*
* Allergy Immunology and Rheumatology Division, Internal Medicine Department, Faculty of Medicine,
Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Affiliation :
Background : Optimal outcome of treatment in rheumatoid arthritis (RA) is early clinical remission to delay joint damage.
Therefore, severe RA patients with inadequate response to conventional disease modifying anti-rheumatic drugs (cDMARDs)
need high potency drug as biological DMARDs (bDMARDs). In general, one-third of RA patient could not get into disease
remission with cDMARDs, and half of them are still suffering from severe arthritis. However, high cost of this agent is the
major barrier for patient engagement, and it is affordable to only 5-10% of patients. We need a good strategy to distribute
bDMARDs to patients, especially in limited resource situation.
Objective : We explored the characteristics of RA patients who were currently using biologic agents in Ramathibodi Hospital
to determine the favorable treatment outcome.
Material and Method: The studied patients were RA patients classified according to ACR/EULAR 2010 criteria and using
any biologic agents, between 2010 and 2012. Demographic data and treatment outcome (low disease activity and remission)
were retrieved from patient records. Univariate analysis and generalized estimating equation (GEE) were used to analyze
predicting factors to control disease at one year. Kaplan-Meier and log rank test were used to analyze time to disease
remission or low disease activity.
Results : Patients treated with bDMARDs in Ramathibodi Hospital demonstrated long disease duration (mean 130.7 months)
and severe disease activity (mean DAS28 5.37). At 1-year after treatment, 19.4% and 12.9% of patients achieved low disease
activity (low DAS) and disease remission, respectively. At 3-years after treatment, 88.9% and 45.2% of patients attained
low DAS and remission. Patients who started bDMARDs after 2010 had significantly shorter time to control disease when
compared to patients who started bDMARDs before 2010 (10 months vs. 34 months). Moreover, we observed that patient
who started bDMARDs after 2010 using more cDMARDs (2.5 vs. 1.7, p = 0.02) and higher dose of methotrexate
(10.7 vs. 6.5, p = 0.03). There were no association between disease control status and treatment (methotrexate, prednisolone,
biologic agent) or disease duration. However, the exposed status of biologic agent was associated with low DAS or remission
at the first year of observation (p = 0.004 and 0.04, respectively).
Conclusion : Chance to control rheumatoid arthritis in the level of remission or low disease activity is predicted by time of
bDAMRDs exposure. This result is mainly influenced by dose of methotrexate and number of cDMARDs.
Keywords : Biologic therapy, Efficacy, Rheumatoid arthritis (RA), Registry cohort
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