Clinical, Laboratory, and Imaging Features Between Men and Women With Axial Spondyloarthritis in a Specialized Center in Argentina.

OBJECTIVES: The aims were to estimate the frequency of axial spondyloarthritis (axSpA) in women and to analyze the clinical, laboratory, and imaging differences with respect to men at the time of diagnosis. METHODS: Consecutive patients older than 18 years with a diagnosis of axSpA admitted to the "Reumacheck" SpA program were included between 2017 and 2022. At baseline, all patients underwent clinical assessment, laboratory tests including C-reactive protein and human leukocyte antigen B27, and imaging (plain radiography and magnetic resonance imaging of sacroiliac joints, and ultrasound of heel entheses). All evaluators were blinded to the results of the other evaluations. RESULTS: One hundred sixteen patients with a diagnosis of axSpA were included. The frequency at diagnosis in women was 61.55%. In the univariate analysis, the significant differences between women and men at diagnosis of axSpA were good response to nonsteroidal anti-inflammatory drugs, elevated C-reactive protein, New York Criteria (+), enthesis ultrasound (+), years of education, number of swollen joints, erythrosedimentation rate, and the very low frequency of bone bridges in the magnetic resonance imaging of the sacroiliac joints. In the logistic regression analysis, the dependent variable was "men," and the only feature that was independently associated was having radiographic compromise according to the New York criteria (odds ratio, 2.6). CONCLUSIONS: The frequency of axSpA in women was 61.55%; clinical, laboratory, and imaging differences were observed. Women experienced less radiographic compromise.

Depression as a possible determinant of fatigue in patients with axial spondyloarthritis.

OBJECTIVES: Fatigue is a common comorbidity in patients with axial spondyloarthritis (axSpA), often reported also by those in clinical remission or with moderate disease activity. The aim of this study is to assess the prevalence of fatigue in patients with axSPA, and to investigate possible non-disease-related determinants, with a special focus on depression. METHODS: Patients with axSpA were assessed using the Chalder's Fatigue Questionnaire (CFQ) for fatigue, and the depression subscale of the Hospital Anxiety and Depression Scale (HADS-D) for depression. Ankylosing Spondylitis Disease Activity Score (ASDAS), Bath Ankylosing Spondylitis Functional Index (BASFI) and Health Assessment Questionnaire (HAQ) were also used to assess disease activities and disability. Univariate and multivariate linear regressions were performed to identify possible predictors of fatigue. RESULTS: Out of 119 patients, 53 (44.5%) had fatigue. Patients with fatigue had higher HADS-D, ASDAS, BASFI, HAQ scores. HADS-D was predictive of CFQ score in univariate and multivariate regressions for total CFQ, and for mental and physical subscales. The correlation between HADS-D and CFQ total score was statistically significant also when taking into consideration only patients in clinical remission and with moderate disease activity. Depressed patients had higher CFQ score compared to non-depressed ones, and did not show any difference in CFQ scores when stratified for disease activity or systemic inflammation. CONCLUSIONS: The study found correlation between fatigue and disease activity and depression in patients with axSpA. These findings suggest that depression could represent the major determinant of fatigue in patients with axSpA, independently of clinical activity.

Ten-year clinical outcome of recent-onset axial spondyloarthritis: Results from the DESIR inception Cohort.

OBJECTIVES: This study aimed to evaluate the 10-year clinical outcome of patients with recent-onset axial spondyloarthritis (axSpA). METHODS STUDY DESIGN: The DESIR cohort is an inception cohort of axSpA patients. METHODS DIAGNOSIS AND MANAGEMENT: The diagnosis and management of patients were based on the decision of the treating rheumatologist. METHODS STATISTICAL ANALYSIS: Both complete cases and imputed data analyses were conducted. RESULTS: Of the 708 enrolled patients, 45 were excluded due to a change in the baseline diagnosis, 3 patients died, and 300 were lost to follow-up over the 10years. In the completer population, one patient required bilateral total hip replacement, and 56 patients received a pension due to invalidity. The prevalence of main extra-musculoskeletal features increased from baseline to year 10: psoriasis from 18% to 30%, acute anterior uveitis from 10% to 18%, and inflammatory bowel disease from 5% to 10%. The most frequent comorbidity was hypertension, with an increase from 5% to 15% from baseline to year 10. In the imputed data analysis the estimated proportions of patients with an acceptable status at year 10 were 70% [95% CI: 63; 77] for acceptable PASS, 43% [95% CI: 37; 49] for BASDAI<3, and 48% [95% CI: 41; 56] for ASDAS<2.1. CONCLUSION: These findings suggest that despite a quite favorable 10-year outcome exists for severe outcomes, a large proportion of patients present with an important disease burden reflected by patient-reported outcomes. This information can be valuable for providing patients with information at the time of diagnosis.

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.

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.

Clinical characteristics of non-radiographic axial spondyloarthritis: Results of the Korean Nonradiographic Axial SPondyloArthritis (KONASPA) data.

AIM: To evaluate clinical characteristics and natural history of non-radiographic axial spondyloarthritis (nr-axSpA) using KOrean Nonradiographic Axial SPondyloArthritis (KONASPA) data. METHODS: Data were collected from 11 centers in South Korea. A total of 278 patients with nr-axSpA from January 2018 to July 2020 were included. Demographic data, clinical features, comorbidities, disease activity, medications, and laboratory results were collected. RESULTS: Mean age at symptom onset was 28.2 ± 14.2 years. Of 278 patients, 152 (54.7%) were male. Mean Bath Ankylosing Spondylitis Disease Activity Index at diagnosis was 3.5 ± 2.1. Dyslipidemia was the most common comorbidity (8.4%), followed by hypertension (6.1%). Mean age at diagnosis of nr-axSpA was older in female patients than in male patients (31.8 ± 15.8 years vs 24.9 ± 12.0 years, P < 0.001). Enthesitis and uveitis were more frequently found in female patients than in male patients. Thirty-one (11.1%) participants with nr-axSpA progressed to ankylosing spondylitis. The median follow-up duration was 48 months. In multivariable Cox regression analysis, age at symptom onset (hazard ratio [HR] 0.93, 95% confidence interval (CI) 0.88-0.97, P = 0.006), body mass index (BMI) (HR 1.24, 95% CI 1.06-1.44, P = 0.005) and sacroiliitis grade (HR 1.86, 95% CI 1.19-2.92, P = 0.006) were associated with progression to ankylosing spondylitis. CONCLUSIONS: Results of nationwide data revealed that women with nr-axSpA showed a late disease onset and more extra-articular manifestations than men. Young age at symptom onset, high BMI, and presence of radiographic sacroiliitis at diagnosis were risk factors for progression to AS.

A Benchmarking Study Evaluating Axial Spondyloarthritis Burden in Spain and Other European Countries. Results from the Spanish Atlas and the European Map of Axial Spondyloarthritis (EMAS) Studies.

AIM: To compare the burden of disease in Spanish patients with axial spondyloarthritis (axSpA) vs other European countries (OEC). METHODS: Data from 2846 unselected patients from the European Map of Axial Spondyloarthritis (EMAS) and the Atlas of Axial Spondyloarthritis in Spain (Atlas) were collected through online surveys. Comparative analysis was carried out between Spanish patients (2016) and patients from 12 OEC ( 2017-2018). Socio-demographic characteristics, life habits, and patient-reported outcomes (Bath Ankylosing Spondylitis Disease Activity Index 0-10, spinal stiffness 3-12, functional limitation 0-54, the 12-Item General Health Questionnaire [GHQ-12] for psychological distress 0-12) were compared. Chi-square and Mann-Whitney tests were used for qualitative and quantitative variables respectively. RESULTS: 680 (23.9%) Spanish axSpA patients were compared to 2166 axSpA patients (76.1%) from OEC. Compared to Spain, the OEC group had a higher percentage of females (64.1% vs 52.5%; P < .001) and university-educated participants (51.7% vs 36.9%; P < .001). Spanish patients showed a greater diagnostic delay (8.5 ± 7.7 vs 7.2 ± 8.6 years; P < .001), visits to orthopedic specialists before diagnosis (56.9% vs 25.3%; P < .001), human leukocyte antigen-B27 carriership (77.1% vs 70.1%; P = .003), disease activity (5.7 ± 2.0 vs 5.4 ± 2.0; P = .024), and higher unemployment rates (21.7% vs 9.2%; P < .001). Despite lower rates of diagnosed anxiety and depression, Spanish patients were at higher risk of psychological distress according to the GHQ-12 (5.7 ± 4.5 vs 4.8 ± 4.0; P < .001). CONCLUSION: Compared to European axSpA patients, Spanish patients experience a longer diagnostic delay and greater psychological distress. Being wrongly referred to orthopedic specialists and facing a more precarious labor scenario appear as possible causal factors, highlighting the need to increase the number of rheumatologists, the training of healthcare professionals, and improving axSpA patients' working conditions.

Prevalence of latent tuberculosis before biotherapy initiation in rheumatoid arthritis and spondyloarthritis: data from the Moroccan biotherapy registry.

Before the initiation of biotherapy in the treatment of rheumatic diseases, it is highly recommended for the patients to be screened for latent tuberculosis infection (LTBI). The objective of this study is to identify the prevalence of LTBI among patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) before the initiation of biologic therapy in the Moroccan biotherapy registry (RBSMR). A cross sectional study was conducted using the baseline data of the Moroccan biotherapy registry. Tuberculin skin test or IGRA test or both tests were done before starting anti-TNF treatment for screening LTBI. The comparisons between positive and negative LTBI patients according to rheumatic disease were examined using categorical comparisons. 259 patients were included in this study.94 patients had RA and 165 had SpA. The mean age of the RA patients was 50.49 ± 11.82 years with a majority of females (84%). The mean age for the SpA patients was 36 ± 13.7 years with a majority of males (67.3%). The prevalence of LTBI in the RBSMR was 21.6%. This prevalence was at 24.8% in SpA patients, while it was at 15.9% for RA patients. After the comparison between positive and negative LTBI patients according to rheumatic disease, no demographic, clinical, or therapeutic characteristics were statistically associated with LTBI. This study found that in an endemic TB country like Morocco, a high prevalence of patients with SpA and RA had LTBI, and that RA patients had a lower prevalence than SpA patients.

Exercise capacity in axial spondyloarthritis and associated factors: A cross-sectional controlled study.

OBJECTIVE: To examine the associations between exercise capacity (EC), cardiovascular (CV) risk factors and disease-related variables in axial spondyloarthritis (AxSpA) patients. METHODS: In this cross-sectional controlled study, CV risk profile data, physical activity, 10-year CV event risk estimated by the Framingham model and Ankylosing Spondylitis Disease Activity Score - C-reactive protein were recorded. A maximal treadmill exercise test by Bruce protocol was administered. Analyses of covariance were performed with adjustments for age, smoking status and physical activity level. Linear regression analysis was performed to study the association between EC and related CV risk factors. RESULTS: Thirty-eight patients and 38 age-gender matched controls were recruited between May and October 2014. Patients had significantly lower EC than controls (MD 2.2; metabolic equivalents 0.91-3.49; P = .001). The difference remained significant after adjustments (P = .001). There were significant correlations between EC and age, 10-year CV event risk, body mass index (BMI) and waist circumference for patients and controls (P < .001 and P < .05, respectively). There was a significant relationship between EC and total cholesterol, triglycerides and heart rate recovery (HRR) in patients (P = .04, P < .001 and P = .006, respectively). High-density lipoprotein - cholesterol was significantly higher, and BMI was significantly lower in nonradiographic AxSpA patients (P = .026 and P = .03 respectively). Age and triglyceride levels were found as the significant predictors for EC in the AxSpa group (for age ß = -.105, P = .003; for triglycerides ß = -.016 P = .003). CONCLUSION: Exercise capacity was significantly lower and attenuated HRR was significantly associated with low EC and high 10-year CV event risk in AxSpA patients.

Diagnosing axial spondyloarthritis: estimation of the disease probability in patients with a priori different likelihoods of the diagnosis.

OBJECTIVE: To evaluate the diagnostic value of SpA parameters and their combination for the diagnosis of axial SpA in patients with an a priori different probability of the diagnosis. METHODS: A total of 361 patients with chronic back pain and suspicion of axial SpA (181 referred by primary care physicians or orthopaedists, 180 recruited via an online screening tool) received a structured rheumatologic examination, which resulted into a diagnosis or exclusion of axial SpA. The prevalence of axial SpA indicating the pre-test probability was 40% in the physician-referred subgroup and 20% in the online screening subgroup. Sensitivities, specificities and likelihood ratios for SpA features were determined in both subgroups and the respective post-test probabilities of axial SpA were calculated. RESULTS: The relative diagnostic value of single SpA features varied substantially between the groups with different referral pathways. For instance, HLA-B27 positivity increased the probability of the presence of axial SpA by 35% to 55% in online-screened patients and by 22% to 62% in physician-referred patients. The absence of HLA-B27 resulted in a sharp decrease in the probability of the presence of axial SpA in physician-referred patients (from 40% to 6%). This decrease was less sharp in the online screening group (from 20% to 10%). These differences were especially relevant in patients with a small number (one to two) of positive SpA features. CONCLUSION: The diagnostic value of SpA features varies in different patient populations, which should be considered in the diagnostic approach.

Similar biologic drug response regardless of radiographic status in axial spondyloarthritis: data from the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis registry.

OBJECTIVE: To describe the baseline characteristics, biologic DMARD (bDMARD) response and drug survival of axial SpA (axSpA) patients in the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis (BSRBR-AS) according to radiographic status. METHODS: The BSRBR-AS is a national prospective cohort including axSpA participants classified according to the Assessment of SpondyloArthritis international Society criteria. In this analysis, baseline data of patients starting bDMARDs were compared. Ankylosing Spondylitis Disease Activity Scores (ASDASs) for low disease status, clinically important improvement (CII) and major improvement (MI) at 1 year were used to assess treatment response. Cox proportional hazards analysis was performed after adjusting for clinically relevant confounders. RESULTS: A total of 1145 axSpA patients were included. Higher male prevalence, older age and longer disease duration were seen in the radiographic axSpA (r-axSpA) subgroup. Based on a complete case analysis (290 patients), two-thirds of patients achieved an ASDAS low disease state at 1 year regardless of radiographic status [non-radiographic axSpA (nr-axSpA) 64.2% vs r-axSpA 66.1]. No statistically significant differences were seen between the subgroups in attaining ASDAS CII (nr-axSpA 50.7% vs r-axSpA 44.7%) or MI (nr-axSpA 20% vs r-axSpA 18.7%). Drug survival probability curves were similar for both subgroups and the hazard ratio for nr-axSpA/axSpA was 0.94 (95% CI 0.69, 1.28) when adjusted for sex, age, baseline ASDAS with CRP, smoking status, disease duration, HLA-B27 and prescribed biologic. CONCLUSIONS: Although there appeared to be some differences in the baseline characteristics when exploring this cohort according to radiographic status, which are likely related to the natural history of the disease, the level of biologic response and drug survival was comparable between nr-axSpA and r-axSpA.

The IBIS-Q [IBd Identification of Spondyloarthritis Questionnaire]: A Novel Tool to Detect Both Axial and Peripheral Arthritis in Inflammatory Bowel Disease Patients.

BACKGROUND AND AIMS: Both peripheral and axial spondyloarthritis [SpA] occur in inflammatory bowel disease [IBD] and represent the commonest extra-intestinal manifestation. We aimed to develop an easy and quick questionnaire through psychometric analysis, to identify peripheral and axial SpA in IBD patients within an integrated combined multidisciplinary rheumatological-gastroenterology clinic. METHODS: Initially, SpA-IBD experts generated a 42-item list covering SpA manifestations including spinal, articular, and entheseal involvement. The new questionnaire was administered before routine clinical IBD assessment. On the same day, rheumatological assessment, blinded to both history and questionnaire results, was performed to explore the presence of the Assessment of SpondyloArthritis International Society [ASAS] criteria for SpA, diagnostic criteria for fibromyalgia [FM], and non-specific low back pain [NSLB]. Factorial analysis of questionnaire items to identify the main factors-receiver operating characteristic [ROC] curves for sensitivity/specificity and Youden index for cut-off-were performed. RESULTS: Of the 181 consecutive patients, 56 met the ASAS SpA criteria [prevalence of 30%] with 10 new cases detected [5.5%: seven peripheral and three axial]. Through the psychometric and factorial analysis, we selected 14 items for the final questionnaire [named IBIS-Q]. The IBIS-Q was quick and performed well for detection of axial SpA and peripheral SpA (area under the curve [AUC] 0.88 with 95% confidence interval [CI] 0.830.93). A cut-off of three positive questions had a sensitivity 93% and specificity 77% for SpA patient identification. CONCLUSIONS: The IBIS-Q is a useful and simple tool to use in IBD clinics for SpA detection, with a good statistical performance. Further studies are needed to validate it.

Diagnóstico de espondiloartrite axial em pacientes com fibromialgia / Axial spondyloarthritis diagnosis in fibromyalgia patients

Objetivo: Avaliar pacientes com fibromialgia e dor lombar, bus- cando características clínicas de espondiloatrites axiais. Méto- dos: Neste estudo transversal, cem pacientes com fibromialgia e idades entre 18 e 65 anos foram avaliados. A avaliação consis- tiu em um questionário baseado no braço clínico dos critérios Assessment of Spondyloarthritis International Society para diag- nóstico de espondiloatrites axiais e um questionário de impacto da fibromialgia (Revised Fibromyalgia Impact Questionnaire). Re- sultados: Quando o braço clínico da Assessment of Spondyloar- thritis International Society foi aplicado em pacientes com fibro- mialgia e dor lombar, 80% dos pacientes preencheram os critérios para diagnóstico de espondiloatrites axiais. As principais carac- terísticas de espondiloatrite axial foram dor lombar inflamatória, boa resposta a drogas anti-inflmatórias não esteroidais, artrite e entesite. Pacientes com critérios de espondiloatrites axiais posi- tivos apresentaram maiores níveis séricos de proteína C-reativa (p=0,00035). O valor médio do Revised Fibromyalgia Impact Ques- tionnaire para todos os pacientes avaliados foi 63,6, e não houve di- ferença entre os pacientes que preencheram os critérios e aqueles que não preencheram. Conclusão: Pacientes com fibromialgia e dor lombar frequentemente apresentam características clínicas de espondiloatrite axial, e aqueles que preencheram os crité- rios clínicos para espondiloatrites axiais também apresentaram maiores níveis séricos de proteína C-reativa.

Objective: To evaluate patients with fibromyalgia and back pain for clinical features of axial spondyloarthritis. Methods: In this cross-sectional study, one hundred fibromyalgia patients between 18 and 65 years old were assessed. The assessment consisted of a questionnaire based on the clinical arm ofthe Assessment of Spondyloarthritis International Society criteria for the diagnosis of axial spondyloarthritis and a questionnaire on the impact of fibromyalgia (Revised Fibromyalgia Impact Questionnaire). Re- sults: When the clinical arm of the Assessment of Spondyloarthri- tis International Society was applied in patients with fibromyal- gia and back pain, 80% of the patients met the clinical criteria for diagnosis of axial spondyloarthritis. The main features of axial spondyloarthritis in fibromyalgia patients were inflammatory back pain, good response to non-steroidal anti-inflammatory drugs (NSAIDs), arthritis, and enthesitis. Patients with positive axial spondyloarthritis criteria presented with higher C- reac- tive protein levels (p=0.00035). The mean value of the Revised Fibromyalgia Impact Questionnaire for all patients assessed was 63.6 and there was no difference between patients that met the criteria for axial spondyloarthritis and those who did not. Con- clusion: Patients with fibromyalgia and back pain often present clinical features of axial spondyloarthritis, and those who met the clinical criteria for axial spondyloarthritis also presented with higher levels of C-reactive protein.