Background: The concept of non-radiographic axial spondyloarthritis (nr-axSpA) has revolutionized the classical understanding of axSpA. Indeed, it facilitated the classification of patients with axSpA who did not present substantial structural damage as it was only detectable on magnetic resonance imaging of the sacroiliac joints (MRI-SIJ) [1]. Continuous non-steroidal anti-inflammatory (NSAIDs) intake has been reported as a potential factor reducing the sensitivity of MRI-SIJ to detect bone marrow edema (BME).

Objectives: The aim of the study was to investigate the effect of continuous NSAIDs intake on BME in nr-axSpA.

Methods: We undertook a cross-sectional study including nr-SpA according to the ASAS criteria and treated with NSAIDs at baseline. Socio demographic data as well disease characteristics were recorded. Disease activity parameters were also collected including the duration of morning stiffness, night awakenings, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). MRI-SIJ was performed for all the patients. All the images were screened for bone marrow edema with the corresponding sequence (short tau inversion). Patients were grouped according to NSAIDs intake: G1: continuous versus G2 occasional. The level of significance was fixed for p<0.05.

Results: The study included 43 nr-axSpA patients. There was a female predominance with a sex ratio of 0.43. The mean age of the patients was 42±12 years [20-71] and the mean disease duration was 17±9.7 years [4-38]. The mean morning stiffness duration was 47.3±45.6 [15-240] minutes. The mean spinal VAS was 5.9±2.6 [0-10]. Nearly 41% of the patients had an active disease with a mean BASDAI of 4.7± 2.1 [0-8.6]. The prescribed NSAIDs were as follows: Diclofenac (44 %), Indomethacin (8%), Ketoprofen (18%), Meloxicam (3%), Celecoxib (3%), Piroxicam (3%) and Naproxen (21%). Nearly half of the patients were continuously taking NSAIDs (52.6%) versus occasional intake (47.4%). Four patients failed two NSAIDs and were treated with a third one. Both groups were comparable for age (p=0.193), sex (p=0.386), and disease duration (p=0.4). Similarly, there were no statistically significant differences regarding disease activity parameters between both groups: numerical rating scale of pain (p=0.713), ESR (p=0.314), CRP (p=0.644), morning stiffness (p=0.428), night awakening (p=1), as well as BASDAI (p=0.514). Regarding MRI-SIJ findings, hyper signal in STIR sequence was comparable between both groups (G1: 35% vs G2:33%, p=0.914). Moreover, the increased signal with Gadolinium injection on T1-weighted images was similar between both groups (p=0.113).

Conclusion: Our study showed that continuous NSAIDs intake was not associated with significant changes in MRI-SIJ features. This study suggests that a NSAID-free period is not necessary before assessing bone marrow edema on MRI-SIJ.

REFERENCES:

[1]Aouad K, De Craemer AS, Carron P. Can Imaging Be a Proxy for Remission in Axial Spondyloarthritis?. Rheum Dis Clin North Am. 2020;46(2):311-25.

Disclosure of Interests: None declared