Objectives To evaluate the influence of tumor necrosis factor (TNF) blocker on the radiographic damage in ankylosing spondylitis (AS)
Methods A total of 598 TNF blocker naïve AS patients from the Observation Study of Korean spondyloArthropathy Registry (OSKAR) data were recruited for this study. The subjects were stratified in relation to the using state of TNF blocker. We evaluated collected clinical and radiographic parameters at two different time points. Then we compared radiographic progression between groups. To use the mSASSS, cervical and lumbar spinal radiographs were examined. Patients with a rate of AS progression that was >2 mSASSS unit were considered progressors. Univariable and multivariable regression analyses were done after adjusting for potential confounding factors, such as age, gender, disease duration, history of eye involvement, history of peripheral arthritis, juvenile onset AS, baseline CRP level, baseline mSASSS, and NSAID intakes).
Results The mean age (SD) of the AS patients was 38.1 (9.2) years, and the mean disease duration (SD) was 9.8 (7.2) years at baseline. In this data, 88.5% of the patients were male, and 96.9% were HLA–B27 positive. 39.8% of the patients had history of peripheral arthritis. Of these patients, 45.3% (271 patients) had received TNF blockers. The mean mSASSS unit (SEM) at baseline was not significantly different between groups (TNF blocker naïve 16.40±0.88 vs TNF blocker user 19.16±1.12, P=0.054). Radiographic follow-up duration from the first mSASSS assessment were comparable (5.48±0.08 vs 5.57±0.08, P=0.447). However, Patients treated with TNF blockers had a higher CRP level (2.52±0.19 vs 1.59±0.10, p<0.01) and longer disease duration (11.70±0.45 vs 8.40±0.37, p<0.01) at baseline. On simple analysis, the TNF blocker naïve patients had less radiographic progression than those with TNF blocker (2.21±0.54 vs 4.48±0.80, p=0.020). After adjustment for multiple comparisons by the Bonferroni correction, gender, history of peripheral arthritis, disease duration, baseline mSASSS, and NSAID intake had statistically significance in our registry. However, the radiographic progression between groups was no significant difference (OR 0.87, [95% CI 0.42-1.81], P=0.71).
Furthermore, we stratified groups according to the proportion of disease duration exposed to TNF inhibitor (0%, <25%, 25-50%, ≥50). On simple analysis, there was a significant difference in the rate of progression in patients who continued the medication for ≥50% of their disease duration as compared to the naive patients (7.53±1.41 vs 2.21±0.54, p=0.028). However, there was no difference of radiographic progression between groups (7.61±1.99 vs 2.83±0.79, p=0.18).
Conclusions Treatment with TNF inhibitors has no influence on radiographic progression in AS.
Disclosure of Interest None declared