Spondyloarthritis in Latin America: a difficult-to-diagnose challenge.

Spondyloarthritis (SpA) presents unique diagnostic challenges in Latin America (LATAM) due to genetic, clinical, healthcare, and sociocultural factors. The Assessment of SpondyloArthritis international Society (ASAS) classification criteria-developed mainly in North America and European populations-may not accurately reflect the LATAM phenotypic variability. Key issues complicating diagnosis include lower human leukocyte antigen B27 (HLA-B27) prevalence, clinical heterogeneity, and inconsistent symptom presentation. Many patients develop symptoms later in life compared to their European counterparts. Extra-articular manifestations like uveitis, enthesitis, and tarsitis are common and may precede the diagnosis, contributing to delays. In addition, inflammatory back pain, often used as a referral criterion, has limited specificity and may lead to misdiagnosis. Healthcare systems in LATAM are often under-equipped to recognize and manage SpA efficiently. General practitioners (GPs) and even non-rheumatologist specialists may lack awareness of hallmark symptoms, leading to prolonged referral processes and multiple misdiagnoses. The average diagnostic delay is around 4.2 years, with women facing even longer delays. Use of classification criteria as diagnostic tools further complicates timely recognition. The ASAS criteria often exclude HLA-B27-negative patients and those without clear imaging findings in sacroiliac joints. This leads to underrepresentation in clinical studies and underestimation of disease burden. To improve diagnosis, a comprehensive clinical evaluation-including history, physical exam, imaging, and laboratory test-by rheumatologists familiar with the local disease spectrum. Tools like magnetic resonance imaging, enthesitis indices (e.g., Mander Enthesis Index, Defining Enthesitis on Ultrasound in Spondyloarthritis Enthesitis Index), and spinal mobility measures (e.g., Bath Ankylosing Spondylitis Metrology Index) should be integrated into clinical practice. There is also a need to validate diagnostic and classification criteria specifically for LATAM populations, incorporating region-specific genetic and clinical profiles. Greater awareness, earlier specialist referral, and locally tailored criteria are essential to reduce diagnostic delays and improve outcomes for patients with SpA in LATAM.