Glucocorticoid-Sparing Effect of Biologic Therapy in Rheumatoid Arthritis: A Single-Center Longitudinal Observational...

Glucocorticoids (GCs) remain an important component of rheumatoid arthritis (RA) management because of their rapid anti-inflammatory effects. However, prolonged exposure to GCs is associated with significant adverse events. Current recommendations advocate minimizing GC use through rapid tapering and discontinuation whenever clinically feasible. This study aimed to evaluate the GC-sparing effect of biologic therapy in patients with RA and to compare outcomes between rituximab and anti-TNF agents.

This longitudinal, observational, single-center study included adult patients who fulfilled the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for RA and started rituximab or anti-TNF therapy while receiving long-term GC treatment for more than three months at a prednisone-equivalent dose greater than 5 mg/day. Patients were assessed at baseline and after four and six months of treatment for GC dose, disease activity (Disease Activity Score in 28 joints based on CRP (DAS28-CRP)), inflammatory markers (CRP and ESR), and functional disability (Health Assessment Questionnaire (HAQ)). The primary outcome was the proportion of patients achieving a GC dose ≤5 mg/day at six months. Secondary outcomes included mean GC doses at four and six months, complete GC withdrawal, and comparison of GC dose reduction between treatment groups.

Sixty patients were included, with a mean age of 52.6 ± 11.6 years, and 58 (96.7%) were female. Twenty-nine patients received rituximab, and 31 received anti-TNF therapy. The mean GC dose decreased significantly from 8.74 ± 1.93 mg/day at baseline to 7.11 ± 2.28 mg/day at four months and 6.07 ± 2.07 mg/day at six months (F = 53.4, p < 0.001). At six months, 31 patients (51.7%) achieved a GC dose ≤5 mg/day, whereas complete GC withdrawal was achieved in only one patient (1.7%). Baseline DAS28-CRP was significantly lower in patients who achieved a GC dose ≤5 mg/day at six months than in those who remained on >5 mg/day (4.82 ± 0.77 vs. 5.36 ± 0.96, t = 2.44, p = 0.02). GC doses decreased significantly over time, with significant differences across all study visits (all post hoc comparisons, p < 0.01). No significant differences were observed between the rituximab and anti-TNF groups in GC doses at baseline, four months, or six months, or in the mean GC dose reduction from baseline to six months (-2.55 ± 1.70 vs. -2.77 ± 2.40 mg/day, t = 0.41, p = 0.68).

Biologic therapy was associated with a significant GC-sparing effect in patients with RA, with a progressive reduction in GC exposure during the first six months of treatment. More than half of the patients achieved a prednisone-equivalent dose ≤5 mg/day, although complete GC withdrawal remained uncommon. No superiority of rituximab over anti-TNF agents was observed regarding the GC-sparing effect. Given the relatively small sample size (n = 60), larger prospective multicenter studies are warranted to confirm these findings.