Differentiating nonradiographic axial spondyloarthritis from its mimics: a narrative review.

BACKGROUND: Optimal treatment of nonradiographic axial spondyloarthritis depends on accurate and timely diagnosis of the underlying disease; however, patients present with common symptoms that, in the absence of radiographic changes, may confound diagnosis. METHODS AND FINDINGS: In this narrative review, a PubMed literature search was conducted through January 2021, with no date limits, to identify English-language publications discussing classification of nonradiographic axial spondyloarthritis, with an emphasis on clinical features and presentation, differential diagnoses, and mimics of disease. This review describes the epidemiology, clinical features, and burden of disease of nonradiographic axial spondyloarthritis as it relates to the overall axial spondyloarthritis spectrum and discusses mimics and differential diagnoses of nonradiographic axial spondyloarthritis that should be considered when evaluating patients with suspected nonradiographic axial spondyloarthritis in clinical practice. CONCLUSIONS: Recognition of clinical features of nonradiographic axial spondyloarthritis, along with an understanding of comorbid conditions such as fibromyalgia, allows for differentiation from its mimics. Appropriate diagnosis of nonradiographic axial spondyloarthritis is important for aggressive management of disease to reduce pain, avoid loss of function, and improve quality of life.

Axial spondyloarthritis.

Axial spondyloarthritis (axSpA) encompasses both radiographic and non-radiographic axSpA. It is a chronic inflammatory disease with a predilection for involving the axial skeleton. The most common presenting symptoms are chronic back pain and spinal stiffness but peripheral and extra-musculoskeletal manifestations occur also frequently. The diagnosis of axSpA relies on the recognition of a clinical pattern of the disease, based on clinical, laboratory and imaging features. The Assessment in SpondyloArthritis international Society classification criteria for axSpA are valid and well implemented for research purposes. Sustained disease activity, measured by validated tools such as the Ankylosing Spondylitis Disease Activity Score, leads to irreversible structural damage and poor functioning and therefore should be abrogated. As part of the management algorithm, non-steroidal anti-inflammatory drugs remain as the first line of pharmacological treatment besides physiotherapy. As a second line, tumour necrosis factor inhibitor and interleukin-17 inhibitor are available but recently Janus kinase inhibitors have also shown efficacy in improving symptoms of the disease.

Comparison of clinical characteristics between adult-onset and juvenile-onset non-radiographic axial spondyloarthritis in Chinese patients: results from the COCAS cohort.

BACKGROUND: Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease predominantly affecting the axial skeleton. We aimed to describe the clinical characteristics of patients with non-radiographic axSpA (nr-axSpA) in China and compare the differences between adult- and juvenile-onset cases. METHODS: A cross-sectional study was conducted using data from 776 patients with nr-axSpA in the Clinical Characteristic and Outcome in Chinese Axial Spondyloarthritis (COCAS) study cohort. Patients were divided into two groups including the adult-onset group (n = 662) and the juvenile-onset group (n = 114) according to age at disease onset. Baseline demographics and clinical characteristics were compared between patients with adult-onset and juvenile-onset nr-axSpA. RESULTS: Overall, the male-to-female ratio was 1.26:1, the prevalence of HLA-B27 positivity was 72.2%, and the median age at disease onset of nr-axSpA was 22 years. Nearly 75% of nr-axSpA patients had peripheral arthritis in the disease course, and the prevalence of extra-articular manifestations was 10.4%. The juvenile-onset group contained a higher proportion of men (66.7% vs. 53.9%, P = 0.011) and a longer baseline disease duration (4.0 [4.0] vs. 1.6 [3.5], P < 0.001) than the adult-onset group. A family history of spondyloarthritis was more frequent in the juvenile-onset group than in the adult-onset group (23.7% vs. 15.4%, P = 0.028), but no significant difference in the prevalence of HLA-B27 positivity was observed between the two groups (P = 0.537). Regarding initial symptoms, peripheral arthritis occurred more often in patients with juvenile-onset nr-axSpA, whereas patients with adult-onset nr-axSpA presented more frequently with axial involvement. The prevalence of inflammatory back pain (IBP) was higher in the adult-onset group than in the juvenile-onset group (85.0% vs. 75.4%, P = 0.010), whereas the juvenile-onset group showed a higher prevalence of peripheral arthritis and enthesitis than the adult-onset group (67.5% vs. 48.5%, P < 0.001; 35.1% vs. 23.3%, P = 0.007, respectively). CONCLUSIONS: Compared with adult-onset nr-axSpA, juvenile-onset nr-axSpA was more common in men and those with a family history of spondyloarthritis. Juvenile-onset nr-axSpA presents with a "peripheral predominant" mode at disease onset and a higher frequency of peripheral arthritis and enthesitis during the disease course.

Participación laboral en espondiloartritis axial radiográfica y no radiográfica / Labor participation in radiographic and non-radiographic axial spondyloarthritis

Introducción: las limitaciones laborales son un punto importante a considerar en el tratamiento de la espondiloartritis axial (EspAax) dado que esta enfermedad afecta a las personas en la etapa más productiva de la vida. Objetivos: describir la situación laboral en pacientes con EspAax de Argentina, incluyendo la espondilitis anquilosante (EA) y la espondiloartritis axial no radiográfica (EspAax-nr), y evaluar los factores asociados a la pérdida de productividad laboral (PPL) en esta cohorte nacional y los factores asociados a estar empleado. Materiales y métodos: en este estudio transversal y multicéntrico se incluyeron pacientes con diagnóstico de EA y EspAax-nr según los criterios de clasificación de la Assessment of SpondyloArthritis international Society (ASAS 2009) y en edad laboral (≤65 años). Los objetivos principales fueron evaluar la situación laboral, el ausentismo y el presentismo, valorados por el cuestionario Work Productivity and Activity Impairment Spondyloarthritis (WPAI-SpA). Se utilizó el coeficiente de Spearman para evaluar la correlación entre las medidas de la enfermedad y la PPL. Se realizó un análisis bivariado y multivariado para evaluar los factores asociados a estar empleado. Resultados: se incluyeron 129 pacientes con EspAax, 95 (73,6 %) con EA y 34 (26,4%) con EspAax-nr. La mediana (p25-75) de edad fue de 45 (35-55) años. La duración mediana de la enfermedad fue de 62 (24-123) meses y el retraso en el diagnóstico fue de 24 (6-72) meses. Sesenta (46,5%) pacientes estaban empleados. La mediana (p25-75) de presentismo de los pacientes con EA fue del 29,6% (0-57) y del 30% (20-40) para los pacientes con EspAax-nr (p=0,02). Asimismo, la mediana (p25-75) de PPL fue del 30% en ambos grupos de pacientes. Se encontró una correlación positiva entre la PPL y las siguientes variables: ASDAS (Rho:0.60), BASDAI (Rho:0.50), BASFI (Rho:0.60), ASQoL (Rho:0.60) y ASAS health index (Rho:0.54). En el análisis bivariado, los factores asociados al desempleo fueron el diagnóstico de EA, la edad avanzada, la mayor duración de la enfermedad, las comorbilidades (hipertensión y diabetes), el menor número de años de educación, la peor calidad de vida y la menor capacidad funcional. En el análisis multivariado, una mejor función física (evaluada por BASFI) se asoció de forma independiente a estar empleado. Conclusiones: este estudio demostró que la PPL en esta cohorte nacional fue del 30% en la EspAax. Se asoció con la actividad de la enfermedad, el estado de salud, la calidad de vida y la capacidad funcional. Una mejor función física se relacionó en forma independiente con una mayor probabilidad de mantener a los pacientes con EspAax empleados.

Introduction: work disability is an important outcome in the treatment of spondyloarthritis (SpA) since this disease affects people in the most productive stage of life. Objectives: to investigate working status in patients with axial spondyloarthritis (axSpA) from Argentina, including ankylosing spondylitis (AS) and nonradiographic axial SpA (nr-axSpA), and to evaluate factors associated with work productivity loss (WPL) in this national cohort and factors associated with being employed. Materials and methods: patients with a diagnosis of AS and nr-axSpA according to Assessment of SpondyloArthritis international Society (ASAS 2009) classification criteria and in working age (≤65 years) were included in this multicentric cross-sectional study. Outcomes of interest were employment status, absenteeism and presenteeism, assessed by the Work Productivity and Activity Impairment Spondyloarthritis (WPAI-SpA) questionnaire. Spearman's coefficient was used to assess the correlation between disease measures and WPL. Bivariate and multivariate analysis were performed in order to evaluate factors associated with being employed. Results: 129 patients with axSpA were included, 95 (73.6%) with AS and 34 (26.4%) with nr-axSpA. Median (p25-75) age of 45 (35-55) years. Median (p25-75) disease duration was 62 (24-123) months and diagnosis delay was 24 (6-72) months. 60 (46.5%) of the patients were employed. Median (p25-75) presenteeism of AS patients was 29.6% (0-57) and 30% (20-40) for patients with EspAax-nr (p=0.02). Median (p25-75) WPL was 30% in both groups of patients. A positive correlation was found between WPL and the following variables: ASDAS (Rho:0.60), BASDAI (Rho:0.50), BASFI (Rho:0.60), ASQoL (Rho:0.60) and ASAS health index (Rho:0.54). In the bivariate analysis, the factors associated with unemployment were AS diagnosis, older age, longer disease duration, comorbidities (hypertension and diabetes), fewer years of education, worse quality of life and lower functional capacity. In the multivariate analysis, better physical function (assessed by BASFI) was independently associated with being employed. Conclusions: this study showed that WPL in this national cohort was 30% in axSpA. It was associated with disease activity, health status, quality of life and functional capacity. Better physical function was independently associated with a higher likelihood of keeping patients with axSpA employed.