Association Between Anti-cyclic Citrullinated Peptide (CCP) Antibody Titers and Oral Prednisolone Tapering in Newly Diagnosed Rheumatoid Arthritis: A Retrospective Cohort Study on Methotrexate Efficacy

Background: This study examined the association between baseline anti-cyclic citrullinated peptide (anti-CCP) titers and oral prednisolone tapering in patients with newly diagnosed rheumatoid arthritis (RA), emphasizing methotrexate (MTX) efficacy. Methods: A retrospective cohort of 230 RA patients from Mashhad, Iran (2019 - 2021) was stratified by prednisolone use (reduction/discontinuation vs. stable) and anti-CCP titers [high: > 3 × upper limit of normal (ULN); low: 1 - 3 × ULN; normal: ≤ 1 × ULN]. The MTX dose was 10 - 15 mg/week. C-reactive protein (CRP) was measured via immunoturbidimetry. Logistic regression was used to assess the relationship between anti-CCP titers and prednisolone reduction/discontinuation, adjusting for potential confounders such as age, sex, and medication use. A P-value < 0.05 was considered statistically significant. Results: 36.5% (84/230) of patients reduced/discontinued prednisolone. The MTX users had higher odds [odds ratio (OR): 3.022, 95% CI: 1.82 - 5.01, P < 0.001]. No association with anti-CCP titer was observed (P = 0.484). However, logistic regression revealed that patients using MTX (as the reference group) had a significantly higher likelihood of reducing/discontinuing prednisolone (OR: 3.022, P < 0.001). Conclusions: This study found no significant relationship between baseline anti-CCP titers and the reduction/discontinuation of prednisolone in RA patients after 18 months of follow-up. However, MTX use was independently associated with a higher likelihood of reducing or discontinuing prednisolone, suggesting potential implications for treatment strategies in RA management.