Background The involvement of the enthesis in the patients with spondyloarthritis (SpA) can be a factor of disability. The efficacy of the TNF antagonists on the SpA activity is well established and is similar between all the drugs available at the moment. On the other hand, the efficacy of the anti-TNF treatment on the enthesitis is not as well-known and doesn't seem as strong as its effect on the overall disease activity.
Objectives To analyze the effectiveness of anti-TNF drugs in the treatment of enthesitis in patients with SpA.
Methods A retrospective analysis of all patients with SpA that started or switched treatment with TNF antagonists in a rheumatology department of a Portuguese University Hospital. The data were collected from the national database for rheumatic patients between July/2012 and December/2013. The demographic and clinic baseline data, disease activity (ASDAS and BASDAI) and functional impairment (determined with BASMI and BASFI) at baseline, 3 and 9 months of therapy were collected. The variations in the enthesitis scores (SPARCC and MASES) were then determined, as well as their difference according to the ASDAS response and according to the diagnosis (ankylosing spondylitis (AS) vs. psoriatic arthritis (PsA)).
Results In December 2013, 26 patients met the inclusion criteria; 61.5% were women, and the median disease duration was 13.5 years. Of the 26 patients, only 10 have HLA B27 determination registered on the database, which was positive in 90% of them. 53.8% of the patients were receiving treatment with a classic DMARD; 50% of them were TNF naïve, and the remaining 50% have already been treated with at least 1 anti-TNF, without adequate improvement in the disease activity. 57.7% have started golimumab, 23.1% adalimumab and 19.2% etanercept. The median baseline BASDAI was 6.4, ASDAS 4.2, and BASMI 4.8.
ASDAS and BASDAI had a significant reduction at 3 months of treatment (p<0.0001 and 0.001 respectively), but at 9 months only the ASDAS reduction was significant (p=0.002). At 3 and 9 months, despite a trend to reduction in the MASES score, none was statistically significant: MASES score showed a reduction of 3.5 points at 3 and 9 months; SPARCC didn't varied between all the evaluations.
The MASES and SPARCC scores didn't differed significantly between the patients with and without ASDAS response, despite a tendency to a greater reduction on both scores on the patients with ASDAS response at 3 months of treatment (reduction of 4 points in MASES and 2 points in SPARCC vs. reduction of 2.5 points in MASES and 1.5 points in SPARCC on the patients with and without ASDAS response respectively).
Between the patients with AS and PsA there weren't any significant differences between the MASES and SPARCC scores, despite an trend towards a greater reduction at 3 months in the ones with AS (reduction of 4 points in MASES and 2 points in SPARCC in AS vs. reduction of 2.5 points in MASES and -1.5 in SPARCC in PsA).
Conclusions This analysis suggests an improvement in the both the enthesitis scores with the introduction of anti-TNF treatment, especially in MASES at 3 and 9 months, and this response occurs in both AS and PsA groups. It also shows that the reduction of the enthesitis scores seems to be independent of the response of the overall disease activity to the treatment.
Disclosure of Interest None declared