Remission Rate of Rheumatoid Arthritis Patients and Associated Factors in Rheumatology Clinic, Khon Kaen Hospital

Abstract

Background and Objective: Rheumatoid arthritis (RA) is the most common of connective tissue disease and vary with prevalence in worldwide population. Remission rates still vary and several factors are involved. However, there was no previous systematic study in KhonKaen hospital. This research aimed to describe the remission rate and factors affecting treatment outcome of RA in KhonKaen hospital.

Methods: Cross-sectional study was performed on RA patients during January 2019–January 2020 who met American college of Rheumatology(ACR) 1987 revised criteria for the classification of RA or 2010 Rheumatoid Arthritis Classification Criteria for RA. We included patients older than 18 years-old who has been treated with ≥ 1 disease-modifying anti-rheumatic drugs (DMARDs) at least 1 year. Demographic data including characteristics of disease, laboratory and radiographic results, pattern and number of current DMARDs used, and disease activity score of 28 joints (DAS 28) were collected from RA database. Remission of disease define as achieving treatment target (DAS 28 < 3.2).

Results: A total of 320 RA patients recruited in this study was classified as female at the proportion of 263 (82.2%). Mean age of onset was 56.5 (SD17.6) years and disease duration was 71(IQ = 79) months. 41% (46 patients) of hypertension and 49.7% (159 patients) of secondary osteoarthritis were the common comorbidity diseases. The serology found positive rheumatoid factor (RF) of 45.3%.  42.2% had erosion before treatment.  The combination of > 2 DMARDs (57.8%) was found to be the most common treatment pattern in which the main drug was methotrexate (92.8%). The median duration of prednisolone use was 15.5 (IQ = 26) months with mean amount of 2.5 (SD = 5) mg. For the outcome of treatment, 50 RA patients (15.6 %) were in remission (DAS 28 < 3.2), 70.3% of moderate (DAS 28 > 3.2 – 5.1) and 14.1% of high (DAS 28 > 5.1) disease activity. Factor associated with remission was < 2 current DMARDs (OR 2.08, 95% CI = 1.0-4.31) while factors associated non-remission were  comorbidity of disease (OR 0.41, 95% CI = 0.19-0.92) and secondary osteoarthritis (OR 0.26, 95% CI = 0.10-.0.70).

Conclusion: The 50 cases (15.6%) of RA patients were in remission, defined as achieving treatment target (DAS 28 < 3.2). < 2 current DMARDs was a factor associated with remission whereas a comorbidity disease and secondary osteoarthritis were associated with non-remission among these patients.