Prevalence of Systemic Lupus Erythematosus in Spain: Higher than Previously Reported in other Countries?

[Abstract] Objectives: Prevalence of SLE varies among studies, being influenced by study design, geographical area and ethnicity. Data about the prevalence of SLE in Spain are scarce. In the EPISER2016 study, promoted by the Spanish Society of Rheumatology, the prevalence estimate of SLE in the general adult population in Spain has been updated and its association with sociodemographic, anthropometric and lifestyle variables has been explored. Methods: Population-based multicentre cross-sectional study, with multistage stratified and cluster random sampling. Participants were contacted by telephone to carry out a questionnaire for the screening of SLE. Investigating rheumatologists evaluated positive results (review of medical records and/or telephone interview, with medical visit if needed) to confirm the diagnosis. To calculate the prevalence and its 95% CI, the sample design was taken into account and weighing was calculated considering age, sex and geographic origin. Multivariate logistic regression models were defined to analyse which sociodemographic, anthropometric and lifestyle variables included in the telephone questionnaire were associated with the presence of SLE. Results: 4916 subjects aged 20 years or over were included. 16.52% (812/4916) had a positive screening result for SLE. 12 cases of SLE were detected. The estimated prevalence was 0.21% (95% CI: 0.11, 0.40). SLE was more prevalent in the rural municipalities, with an odds ratio (OR) = 4.041 (95% CI: 1.216, 13.424). Conclusion: The estimated prevalence of SLE in Spain is higher than that described in most international epidemiological studies, but lower than that observed in ethnic minorities in the United States or the United Kingdom

Utilidad de Trabecular Bone Score en la detección de osteoporosis en pacientes con Espondilitis Anquilosante y Espondiloartitis Axicial no radiográfica

Introducción: Las Espondiloartritis (EspA) son un grupo de enfermedades que se caracterizan por la formación de hueso nuevo siendo los sindesmofitos la lesión característica en la EspA axial. A pesar de ésto, la osteoporosis es la comorbilidad más frecuente, presentando un aumento en el riesgo de fracturas vertebrales, al producir una pérdida de hueso trabecular. Entre los factores de riesgo de baja densidad mineral ósea se encuentran el daño radiológico y la elevación de PCR y VSG. La absorciometría con rayos X de doble energía (DXA), técnica gold-estándar para el diagnóstico de osteoporosis (OP), se ve influenciada por los sindesmofitos dando valores falsamente elevados. Además, no es capaz de distinguir entre los diferentes compartimentos óseos. La puntuación de hueso trabecular (TBS) es una medida indirecta de la microarquitectura cuyos valores no parecen estar sobreestimados por los cambios degenerativos en la columna lumbar. Objetivos: Analizar los valores de TBS en pacientes con Espondilitis Anquilosante (EA) y EspAax no radiográfica (EspAax-nr) y correlacionarlos con los valores de DMO obtenidos mediante DXA. Material y métodos: Estudio transversal en el que se evaluó los valores de TBS y DMO mediante DXA en pacientes con EspAax (EspAax-nr y EA). Se incluyó un grupo comparador con sujetos con situaciones clínicas, diferentes a enfermedades reumáticas inflamatorias, asociadas a un mayor riesgo de OP y fractura por fragilidad. Se recogieron variables clínico-demográficas, relativas a la enfermedad y analíticas. Se utilizó el modelo de regresión lineal para determinar los factores de riesgo asociados a TBS. Resultados: Se incluyeron 82 sujetos con EspAax (59 EA y 23 EspAax-nr) y 30 sujetos en el grupo comparador. El valor de TBS medio en el grupo de EspAax-nr fue 1,45 ± 0,10 y en EA de 1,35 ± 0,13 (p = 0,001). Se encontró correlación positiva entre TBS y DMO lumbar y cuello femoral en EA. Se asociaron con mayor riesgo de fractura por TBS, el IMC, duración de la enfermedad, VSG y número de niveles afectados por sindesmofitos. El TBS bajo se correlacionó con la edad, VSG y PCR en el grupo de EspAax-nr; DMO lumbar y cuello femoral en EA, y con la presencia de sindesmofitos, grado de sacroilitis, VSG, edad y DMO en cuello femoral en el conjunto de EspAax. El grupo de EspAax con sindesmofitos presentó valores de TBS más bajos (p = 0,006) en comparación con los que no los presentaba. El grupo comparador presentó valores más bajos de TBS que el grupo de EspAax Conclusiones: - TBS en pacientes con EA fue inferior respecto a los pacientes con EspAax-nr, indicando una peor calidad ósea en pacientes con EA. - TBS se correlacionó de manera positiva con los valores de DMO lumbar y cuello femoral en EA. Esta correlación no se observó en pacientes con EspAax-nr. - TBS aportó información adicional a la DMO en un tercio de pacientes con EspAax, especialmente en pacientes con EA donde lo alcanzó en prácticamente la mitad de los pacientes. - El IMC, duración de la enfermedad, VSG y número de niveles afectados por sindesmofitos se asociaron a un mayor riesgo de fractura por TBS. - Los marcadores analíticos de inflamación sistémica y la edad se identificaron como factores de riesgo independientes de TBS bajo en EspAax-nr; la DMO lumbar y cuello femoral en EA; y la presencia de sindesmofitos, grado de sacroilitis, VSG y edad en el grupo global de EspAax. - TBS encontró una peor calidad ósea en pacientes con sindesmofitos. - Los valores de TBS no parecen estar enmascarados por la presencia de sindesmofitos. - Los pacientes con EspAax presentaron valores más altos de TBS que el grupo comparador.Introduction: Spondyloarthritis (SpA) is a group of diseases that are characterized by the formation of new bone, being syndesmophytes the hallmark of axial SpA. Despite this, osteoporosis is the most frequent comorbidity, presenting an increased risk of vertebral fractures due to a loss of trabecular bone. Among the risk factors of low bone mineral density are radiological damage and elevation of CRP and ESR. Dual-energy X-ray absorptiometry (DXA), gold-standard technique for the diagnosis of osteoporosis (OP), is influenced by syndesmophytes leading to false high values. In addition, DXA is not able to distinguish between trabecular and cortical compartments. Trabecular bone score (TBS) is an indirect measure of the microarchitecture whose values do not seem to be overestimated by degenerative changes in lumbar spine. Objectives: To analyze the TBS values in patients with Ankylosing Spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA), and correlate them with BDM values using DXA. Material and methods: Cross-sectional study evaluating the values of TBS and BMD by DXA in patients with axSpA (nr-axSpA and AS). A comparator group was added including subjects with clinical conditions, different from inflammatory rheumatic diseases, which are associated with an increased risk of OP and fragility fracture. Clinical-demographic variables were collected, related to the disease and laboratory tests. Linear regression model was used to determine risk factors associated with TBS. Results: We included 82 subjects with axSpA (59 AS and 23 nr-axSpA) and 30 subjects in the comparator group. The mean TBS value in the nr-axSpA group was 1,45 ± 0,10 and 1,35 ± 0,13 in AS (p = 0,001). A positive correlation was found between TBS and lumbar BMD and femoral neck in AS. BMI, duration of disease, ESR and number of levels affected by syndesmophytes were associated with an increased risk of TBS fracture. Lower values in TBS was correlated with age, ESR and CRP in the nr-axSpA; lumbar and femoral neck BMD in AS, and with the presence of syndesmophytes, degree of sacroiliitis, ESR, age and BMD in the femoral neck in the overall axSpA group. axSpA group with syndesmophytes had lower TBS values (p = 0.006) compared to those without syndemosphytes. The comparator group had lower TBS values than axSpA group. Conclusions: - Lower TBS values were found in AS compared to nr-axSpA, indicating poorer bone quality in patients with EA than in nr-axSpA. - TBS correlated positively with the values of lumbar BMD and femoral neck in EA. This correlation was not observed in nr-axSpA. - TBS provided additional information to the BMD in a third of patients in axSpA group and almost half of the cases in AS group. - BMI, duration of the disease, ESG and number of levels affected by syndesmophytes were associated with an increased risk of TBS fracture. - Systemic inflammation laboratory markers and age were identified as independent risk factors for low TBS in nr-axSpA; lumbar and femoral neck BMD in EA; and the presence of syndesmophytes, degree of sacroiliitis, ESR and age in the overall axSpA group. - TBS found poorer bone quality in patients with syndesmophytes. - The presence of syndesmophytes did not mask TBS values. - axSpA patients had higher TBS values than the comparator group