Background TNF-inhibitors could significantly improve disease activity of SpA patients, however, there is still no answer to the effect of prolonged the interval of TNF-inhibitors on MRI changes.
Objectives The aim of the study was to investigate whether prolonged the interval of TNF-inhibitor injection could maintain SpA at low disease activity and improve imaging changes of sacroiliac joint.
Methods A total of 98 SpA patients were included and 67 of them received TNF-i with or without conventional DMARDs. TNF-i included Etanercept, Infliximab and Adalimumab. The full dosage treatment was defined as patients received Etanercept 50 mg per week, Infliximab 4 mg/kg at 0, 2, 6 week and Adalimumab 40 mg every two weeks. The dose of Etanercept was gradually reduced to 50 mg every two weeks, 50 mg every three weeks and then 50 mg per month. The infusion of Infliximab was reduced to every 8 weeks, every 12 weeks and then every 16 weeks. The interval of Adalimumub injection was changed from 3 weeks to 4 weeks and then to two months. After full dose treatment in the first 3 months, patients who administrated TNF-i were evaluated every 3–6 months. According to laboratory tests including ESR, CRP and IgA levels, BASDAI, BASFI, ASDAS results and sacroiliac joint SPARCC scores, the interval of TNF-i treatment was prolonged gradually. Fat metaplasia, bone erosion, sclerosis and ankylosis changes on MRI were compared between baseline, 4–6 months and 1–2 years.
Results After 3 months of treatment, inflammatory indexes, BASDI, BASFI, ASDAS and SPARCC scores were significantly lower than baseline (P<0.05). After 4–6 months of treatment, ESR, CRP and IgA levels were greatly lower than before (8 (3,25) vs. 2 (1,3) mm/h, 4.97 (1.83,14.5) vs. 1.71 (1.24,2.82) mg/l, 2.96±1.34 vs. 2.20±1.01mg/l, Table 1, P<0.01). Compared to baseline, significant reduction of BASDAI and BASFI score was observed in TNF-inhibitor group. The SPARCC scores in TNF-i group also decreased significantly (Figure1, P<0.01). There was no significant progress in fat metaplaisa, bone erosions, sclerosis and ankylosis during the follow-up period (P>0.05). Even though the inflammatory indexes and clinical evaluation of non-TNF-i group did not improved remarkably, SPARCC score were significantly reduced at 4–6 months and 1–2 years (P<0.05).
Conclusions TNF-i could reduce clinical and imaging inflammatory degree. Prolonged the interval of TNF-i treatment could maintain low disease activity and improve bone marrow edema, whereas fat metaplasia, bone erosion, sclerosis and ankylosis were not exacerbated.
Disclosure of Interest None declared
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