Background Non-steroidal anti-inflammatory drugs (NSAIDs) are clinically effective and considered as a first line therapy in patients with ankylosing spondylitis (AS). NSAIDs might also have disease-modifying activities retarding radiographic spinal progression in AS. However, it is not clear whether the radiographic response to NSAIDs depends on the presence or absence of risk factors of radiographic spinal progression.
Objectives The objective of the study was to investigate the effect of NSAIDs intake on the radiographic spinal progression in patients with AS in the presence and absence of risk factors for such a progression.
Methods In total, 88 patients with AS according to the modified New York criteria from the German Spondyloarthritis Inception Cohort (GESPIC) have been selected for this analysis based on availability of spinal radiographs at baseline and after 2 years of follow-up and of the data on NSAIDs intake during this period of time. None of the patients included in this analysis received anti-TNF therapy. Radiographs of the cervical and lumbar spine were scored according to the mSASSS independently by two trained readers, who were blinded for time point and all clinical data. Data on NSAIDs intake were collected at baseline and every 6 months thereafter during 2 years of follow-up. An ASAS index of the NSAIDs counting both dose and duration of drug intake was calculated. High NSAIDs intake was defined as a mean NSAID intake index over 2 years of ≥50, low NSAIDs intake – as a mean NSAID intake index <50.
Results Patients with AS and high NSAIDs intake (n=24 or 27%), in comparison to patients with low NSAIDs intake (n=64 or 73%), had a lower rate of radiographic spinal progression as assessed by the change of mSASSS score over 2 years (0.02±1.38 vs. 0.96±2.78 mSASSS units). However, the positive effect of the NSAIDs intake was nearly exclusively evident in patients who were at high risk for radiographic progression due to the presence of syndesmophytes and persistent systemic inflammation. In patients with both, syndesmophytes and elevated (>6 mg/l) time-averaged C-reactive protein (CRP), the mSASSS progression over two years was 4.36±4.53 vs 0.14±1.80 in the groups with low and high NSAIDs intake, respectively (p=0.02), while there was nearly no progression in patients without both risk factors: 0.35±1.07 vs 0.07±1.06, respectively (p=0.48) – figure.
Conclusions Retardation of radiographic spinal progression in AS under NSAID therapy is most prominent in patients who are at high risk for progression. This might have an implication on the choice of the optimal NSAIDs regimen in individual patients in the clinical practice.
Disclosure of Interest None Declared