AB0187 PREVALENCE, RISK FACTORS, AND TREATMENT MODALITIES OF ATLANTOAXIAL DISLOCATION IN RHEUMATOID ARTHRITIS

Background: Cervical spine involvement is common in patients with rheumatoid arthritis (RA). The most common abnormality is atlantoaxial dislocation (AAD). It may lead to severe neurological symptoms and even death. Currently, there is a lack of consensus on the best approach to treatment. Objectives: We investigated the prevalence of and risk factors for AAD in patients with RA, as well as its relationship to treatment modalities. Methods: We conducted a cross-sectional study including 224 patients with RA. All patients fulfilled the 2010 American College of Rheumatology/European League Against Rheumatism RA classification criteria. Radiographs of the cervical spine included lateral views taken in flexion, extension, neutral position of the neck, anteroposterior and odontoid projection view. Patients were divided into two groups: (G1) a group with AAD and (G2) without ADD. We compared clinical, radiological, and laboratory findings between the two groups, as well as the treatments used: Steroid therapy, classic and biologic disease-modifying anti-rheumatic drugs (DMARDs). Structural joint damage was assessed with the Sharp/van der Heijde radiographic method. Functional impairment was assessed using the Health Assessment Questionnaire (HAQ). We used Statistical Package for Social Sciences (SPSS) 22.0 to analyze the results. The level of statistical significance was set at 0.05. Results: ADD was present in 16% of the cases (n=36). Female predominance was noted, with a sex ratio of 0.25 (p=0.530). The mean age was 58±12 years, with no significant difference between groups (p=0.146). The mean disease duration was significantly higher in G1 (11.5 ± 10.5 years versus 5.9 ± 6.3, p=0.004). A noticeable relationship between AAD and immunopositivity was found: rheumatoid factor (RF) was present in 86.1% of the cases in G1 versus 67.5% in G2 (p=0.025). Anti-citrullinated protein antibodies (ACPA) were present in 86.1% of the cases in G1 versus 64.8% in G2 (p=0.012). We found a significant difference between AAD and disease activity assessed by DAS28-VS (5.8±1.3 in G1 versus 5.3±1.6 in G2,p=0.027). AAD was significantly associated with more structural joint damage: erosions (121.1±60.9 in G1 versus 61.8±56.5 in G2,p HAQ score was higher in G1 (1.8±0.7 versus 1.2±1, p=0.002). Seventy-five percent of patients in G1 had received methotrexate versus 82.3% in G2 (p=0.301). The mean duration of methotrexate therapy was longer in G1 (24.6±23.5 versus 18±24 months, p=0.015). G1 patients received a higher mean dose and cumulative dose of methotrexate: 13.2±3.5 g/week versus 11.8±4.4 g/week (p=0.048), and 6.5±6.8 versus 4.8±8.5 (p=0.025), respectively. Thirty-five percent of patients in G1 had received corticosteroids versus 25% in G2 (p=0.217). Patients in G1 had a significantly longer duration of steroid therapy: 17.8 + 20.2 versus 13.3 + 24.3 months (p=0.22). The mean dose of corticosteroids was similar between the two groups: 6.9±4.3 mg/day versus 5.7±4.6 mg/day (p=0.132). The total cumulative dose was significantly higher in G1: 6.5±6.8 mg/day versus 4.8±8.5 mg/day (p=0.025).There was no significant difference in using other DMARDs: Sulfasalazine (p=0.182) and leflunomide (p=0.276). No significant difference was observed with patients under biologic DMARDs: 24.1% in G1 versus 17% in G2 (p=0.725). Conclusion: Cervical spine involvement is common in RA and may be asymptomatic. Immunopositive patients seem to have more frequently ADD, as well as those with high disease activity and severe structural joint damage. The treatment modalities do not appear to be affected by AAD; however, patients with ADD seem to have higher cumulative doses of corticosteroids and methotrexate. Given the cross-sectional nature of our study, it is difficult to confirm the connection between the two. Further studies are needed. Disclosure of Interests: None declared