The Role of HLA-B27 in Argentinian Axial Spondyloarthritis Patients.

BACKGROUND: The prevalence of human leukocyte antigen B27 (HLA-B27) is variable around the world. Our objectives were to estimate the frequency of HLA-B27 in an Argentinian cohort of axial spondyloarthritis (axSpA), to evaluate the differences between HLA-B27-positive and HLA-B27-negative patients, and to analyze its performance as a diagnostic biomarker. METHODS: Observational study including patients older than 18 years, with axSpA diagnosis assessed in a fast track program (Reuma-Check SpA). All patients underwent the following: blood tests, HLA-B27, sacroiliac images, and enthesitis ultrasound. Sociodemographic data and SpA symptoms were also collected. The clinical assessor was blinded to complementary studies. For the sensitivity and specificity analysis, patients with chronic low back pain without axSpA who performed the same circuit in the same period were used as control, paired 1:1 (sex and age). RESULTS: One hundred fifty patients were included, 75 axSpA and 75 controls. The frequency of HLA-B27 was 43% (95% confidence interval [CI], 30-53). The differences between HLA-B27-positive and HLA-B27-negative patients were observed in age of low back pain onset (36 vs 46 years), BASFI (Bath Ankylosing Spondylitis Functional Index) (4 vs 5), and extra-articular SpA features such as uveitis and inflammatory bowel disease (29% vs 50%). When this frequency was compared (low back pain control group), the difference was 43% versus 9% (odds ratio, 7.7; 95% CI, 2.8-24), and HLA-B27 had a sensitivity of 43%, specificity of 91%, positive predictive value of 85%, negative predictive value of 58%, and likelihood ratio of 4.9 (95% CI, 3-8). CONCLUSIONS: The frequency of HLA-B27 in axSpA was 43%; positive patients had an earlier age of onset (36), a higher BASFI, and more SpA features. For the diagnosis of SpA, HLA-B27 had a good specificity but low sensitivity.

"Reuma-Check": Performance of a Comprehensive Fast-Track Program for the Diagnosis of Axial Spondyloarthritis in South America.

OBJECTIVES: The aim of this study was to evaluate the performance of a comprehensive diagnosis program called "Reuma-check" for the diagnosis of axial spondyloarthritis (SpA) in patients with low back pain (LBP). METHODS: This is a cross-sectional study. Patients with LBP aged 18 years or older were preselected, and those with at least 1 SpA feature completed the circuit. They were referred after 2 strategies: education for orthopedists and a campaign on social networks. All patients underwent a clinical evaluation, laboratory testing, and imaging (including human leukocyte antigen B27 evaluation and magnetic resonance imaging). The diagnosis of axial SpA was established by an expert rheumatologist opinion. Time from onset of symptoms to "Reuma-check," time from patient referral to admission of the checkup, and time from "Reuma-check" to diagnosis were evaluated. RESULTS: A total of 175 of 246 patients were included, most of them came from the social media campaign (55%). Seventy-five (43%) of 175 patients were diagnosed as axial SpA. The median time from referral (or self-referral) to access to the program was 1.3 months. The median time from symptoms onset to access to the program was 31.7 months, and the median time from the performance of "Reuma-check" to final diagnosis was 2 weeks. Features associated with a diagnosis of axial SpA were as follows: inflammatory LBP (odds ratio [OR], 6.64; 95% confidence interval [CI], 1.6-28), clinical enthesopathy (OR, 4.56; 95% CI, 1.1-18.4), positive human leukocyte antigen B27 (OR, 23.02; 95% CI, 3.5-58), and positive magnetic resonance imaging (OR, 14.34; 95% CI, 3.5-58). CONCLUSIONS: "Reuma-check" allowed a high frequency of axial SpA diagnosis and improved access to rapid diagnosis, shortening the time from referral to diagnosis with a shorter acquisition time for the ancillary studies. Patients with a final diagnosis of axial SpA presented distinctive features.

EULAR definition of "arthralgia suspicious for progression to rheumatoid arthritis" in a large cohort of patients included in a program for rapid diagnosis: role of auto-antibodies and ultrasound.

OBJECTIVES: To evaluate the performance of the European League Against Rheumatism (EULAR) definition of arthralgias suspicious for progression to RA in patients with hand arthralgias and to estimate the added value of both auto-antibodies and ultrasound (US) with power Doppler (PD). METHODS: Consecutive patients admitted for hand arthralgias to "Reuma-check" ® program were included. This program includes the following at baseline: clinical assessment, laboratory tests, US with PD of both hands, and radiography of both hands and feet. All patients were followed-up after baseline evaluation by their treating rheumatologists, and a definitive diagnosis of RA (ACR/EULAR 2010 criteria) was established or not. RESULTS: A total of 465 consecutive patients were included. During follow-up, 44 (9.4%) were diagnosed with RA. Mean of baseline EULAR features describing arthralgia suspicious for progression to RA was 4.1 in patients with final diagnosis of RA vs 2.3 in non-RA patients (p < 0.0001). The AUC for the EULAR defined features describing arthralgia suspicious for progression to RA for the final diagnosis of RA was 0.7827, while adding US with PD, rheumatoid factor (RF), and anti-cyclic citrullinated peptide antibodies (ACPA) data, the AUC was 0.9172 (p < 0.0001). In the multivariate regression logistic analysis, baseline features associated with a final diagnosis of RA were difficulty with making a fist, RF, ACPA, and US with PD. CONCLUSIONS: EULAR definition of arthralgia suspicious for progression to RA had an acceptable performance to predict the future development of RA and improves adding information of both RF, ACPA and US with PD data.Key Points• Clinically suspect arthralgia may trigger rheumatologists to monitor patients closely for an early diagnosis.• EULAR definition of arthralgia suspicious for progression to RA predicts future development of arthritis.• Auto-antibodies and ultrasound improve EULAR definition of arthralgia suspicious for progression to RA.