Background/Purpose:

There are many studies about impact of TNF-inhibitors on radiographic progression but little data are available on the relationship between treatment agents and sagittal balance in AS. We focus on radiological aspects related to treatment agents and compare sagittal balance treated with anti-TNF-α to non-steroidal anti-inflammatory drugs and sulfasalazine.

Methods:

One hundred thirty three consecutive AS patients were enrolled prospectively. AS patients were eligible to participate in the trial if they were in medical treatment with same treatment agents at least from 1 year. All patients were treated with NSAIDs and sulfasalazine first. 69 patients were showed excellent outcome of pain control with same agents (Group A). But 64 patients complained of intractable low back pain even though treated with same agents. After at least 3 months, we changed treatment agents for these patients to anti-TNF-α therapy (Group B). Radiographic parameters, that is, sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), thoracic kyphosis (TK), lumbar lordosis (LL), horizontal distance between C7 plumb line and the posterosuperior corner of the sacrum (C7PL), sacrofemoral distance (SFD), C7PL/SFD ratio (C7/SFD), spinosacral angle (SSA), spinopelvic angle (SPA), C2-C7 lordosis (CL), C2-C7 sagittal vertical axis (C2-C7 SVA) were measured. For the assessment of clinical outcome, the Bath AS Disease Activity Index (BASDAI) score and erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level were checked. Radiologic and clinical parameters were checked at enrolment, when changing treatment agents and every 6 months during the follow-up period.

Results:

Significantly differences were observed at baseline between two groups. Mean ESR, CRP, and BASDAI were significantly higher in group B. Patients in group B had significantly higher TK compared with group A. In comparison between both groups after treatment, patients in group B had significantly higher lumbar lordosis after treatment. And clinical outcomes including ESR, CRP, BASDAI were significantly lower in group B. At the comparisons between before and after treatment in both groups, there was no significant difference among radiologic parameters in group A. Only BASDAI score had lower after treatment in group A. But in group B, lumbar lordosis and cervical lordosis were significantly increased after treatment. And ESR, CRP, and BASDAI were significantly lower than before treatment. Correlation analysis revealed significant relationships between radiologic parameters and BASDAI. Under multiple regression analysis, lumbar lordosis was the significant predictor for BASDAI.

Conclusion:

This study shows a clear association between treatment agents and radiologic parameters in AS. Furthermore, patients in group B and patients in group A were found to be significantly different in terms of sagittal radiologic parameters like thoracic kyphosis and lumbar lordosis. In addition, correlation analysis revealed significant relationships between radiologic parameters and clinical outcomes. Anti-TNF-α treatment improved lumbar lordosis and made slow thoracic kyphotic progression with improvement of clinical outcomes in AS.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparison-of-radiologic-parameters-of-ankylosing-spondylitis-treated-with-anti-tnf-%ce%b1-versus-non-steroidal-anti-inflammatory-drugs-and-sulfasalazine/