Unstimulated whole salivary flow in Sjögren's Syndrome: systematic literature review and meta-analysis

Abstract Background: Sjögren's Syndrome compromises the exocrine function, producing xerostomia and xerophthalmia. It can appear as an isolated condition or associated with other autoimmune diseases (polyautoimmunity). The Unstimulated Salivary Flow rate (UWSF) is used to quantify saliva production. There is no objective evidence to differentiate the values in patients with Sjögren's versus healthy people or patients with non-Sjögren's sicca. The objective of the present review was to evaluate the UWSF in patients with Sjögren's syndrome in comparison to controls (healthy and non-Sjögren's sicca patients). Methods: A systematic literature review was carried out (PRISMA guidelines). Analytical observational studies of cases and controls, cross-sectional studies, cohort studies and randomized clinical trials (including healthy controls) were considered. The Medline/OVID, Lilacs, Embase, and Cochrane/OVID databases were consulted. MeSH, DeCS, keywords, and Boolean operators were used. The meta-analysis (RevMan 5.2) was done through the random-effects model [mean difference (MD)]. Level and quality of evidence were evaluated by the Oxford Center Levels of Evidence and Joanna Brigs list respectively. Results: Thirty-two articles were included (20 were case-control studies,6 were cross-sectional,2 prospective cohort,2 retrospective cohort, and2 studies were abstracts) and 28 were meta-analyzed. The unstimulated whole salivary flow rate in the Sjögren's group was lower than in controls (healthy and patients with non-Sjögren Sicca syndrome) (MD-0.18 ml/min; 95% CI, −0.24 to −0.13; chi2-P-value <0.00001). Heterogeneity was 97% and there was publication bias (funnel plot). The level of evidence was mostly3 or 4. The quality of evidence was met (97% of items valued). Conclusion: For the first time, the unstimulated whole salivary flow rate is found to be lower in patients with Sjögren's syndrome compared to controls (healthy and non-SS sicca) through a meta-analysis. (AU)

Técnica de recolección del flujo salival no estimulado en el diagnóstico de pacientes con síndrome de Sjögren: unificando conceptos. Una revisión sistemática de la literatura / Unstimulated whole saliva flow collection technique in the diagnosis of patients with Sjögren's syndrome: Unifying concepts. A systematic literature review

RESUMEN El síndrome de Sjögren (SS) es una enfermedad autoinmune que compromete la función de las glándulas exocrinas, produciendo xerostomía y xeroftalmia. El método utilizado para cuantificar la disfunción glandular salival es el flujo salival no estimulado (FSNE). Describir las principales técnicas de recolección del FSNE en pacientes con SS. Revisión sistemática de la literatura (guías PRISMA) de estudios observacionales tipo casos y controles, cohorte y corte transversal que incluyeran pacientes con síntomas secos y diagnóstico de SS por criterios clasificatorios internacionales, que fueran comparados con una población de referencia sana o con síntomas secos no Sjögren y en los cuales se reportara la técnica y el valor del FSNE como desenlace principal. Para la calificación del nivel y calidad de la evidencia se utilizaron las guías Oxford y el Joanna Briggs Institute. Veintinueve artículos fueron incluidos, con una población total de 2.730 pacientes: 1.397 casos y 1.333 controles. La técnica más frecuentemente reportada fue la de Navazesh por recogida espontánea de drenaje durante 5 min. El punto de corte más frecuentemente encontrado fue 0,1 ml/min. Por primera vez se describen, a través de una revisión sistemática de la literatura, las principales técnicas utilizadas para evaluar el FSNE en individuos con SS cuando se comparan con personas sanas o con síndrome seco no SS, resaltando que es una técnica validada, no invasiva, reproducible y de bajo costo.

ABSTRACT Introduction: Sjögren's syndrome (SS) is an autoimmune disease that compromises the function of exocrine glands, producing xerostomia and xerophthalmia. The method used to quantify saliva gland dysfunction is by unstimulated whole saliva flow (UWSF).To describe the main UWSF techniques in patients with SS. Systematic review of the literature (following PRISMA guidelines) of results that include analytical observational studies of case-control, cohort, and cross-sectional studies that include patients with sicca symptoms and diagnosis of SS by international classification criteria, which were compared with healthy subjects or those with non-Sjögren sicca symptoms, and in which the technique and the value of the UWSF was reported as the main outcome. Qualification of the level and quality of the evidence was obtained using the Oxford and Joanna Briggs Institute guidelines. A total of 29 articles were included, with total population of 2,730 patients: 1,397 cases and 1,333 controls. The most frequently reported technique was that of Navazesh by spontaneous drainage collection for 5 min. The most frequent cut-off point found was 0.1ml/min. For the first time in the literature, and by using a systematic review of the literature, a description is presented of the main techniques used to evaluate UWSF in individuals with SS when compared with healthy people or with sicca non-SS syndrome, highlighting that it is a valid, non-invasive, reproducible, and low cost technique.