Diagnostic performance of serology against histologic assessment to diagnose Sjögren’s syndrome

  • Author / Creator
    Luiz Claudio Viegas Costa
  • Many non-communicable chronic diseases are not prevented, controlled or cured because of disease misdiagnosis or overdiagnosis. In both situations, the patients will not benefit from the diagnostic process, instead, the consequences of maltreatment may harm them. For instance, Autoimmune Diseases (AD) are a major public health problem, with a high prevalence and impact on individuals’ general health and well-being. AD patients affected by diagnosis issues face drug side effects, unnecessary tests, extra personal and public costs, with an obvious significant impact on the health system. Sjögren's syndrome (SS) is a good example of an AD, chronic and worldwide prevalent misdiagnosed/undiagnosed disease, for which the diagnostic criteria are still a matter of debate, with many patients going untested and not receiving a confirmed diagnosis. SS is characterized primarily by dry mucous membranes, mainly in oral and ocular membranes, due to the decrease or absence of glandular secretions (Sicca syndrome). SS can also present with extra-glandular involvement, with cutaneous, pulmonary, musculoskeletal, renal, or neurological manifestations. SS shows an estimated prevalence of 1% and a 9:1 female predominance. It is more commonly seen between the ages of 45 to 75. SS patients present a lower quality of life, sometimes similar to that observed in other rheumatic diseases, such as rheumatoid arthritis and systemic lupus. The oral component of SS shows glandular dysfunction (hyposalivation) and a sensation of dryness (Xerostomia). A dry mouth is at a higher risk of periodontal disease and caries, in unusual locations including root and incisal surfaces. The oral soft tissues also are affected by the condition, sometimes with a burning sensation on the tongue or on the oral mucosa, and different forms of candidiasis and mucositis.
    The complexity of the clinical approach demands an accurate SS diagnosis. American College of Rheumatology and the European League Against Rheumatism (ACR/EULAR) new diagnostic criteria indicate that either salivary gland (SG) biopsy or anti-SSA must be positive, corroborating their central role in the diagnostic process. However, some authors and centres have suggested that the SG biopsy could be circumvented, and that only clinical and serological features are required to define the diagnosis Subtle changes in the ACR/EULAR criteria have been explored in an attempt to improve accuracy, such as increasing the threshold score from 4 to 5 out of 9 possible points. Nevertheless, in the clinical setting, some rheumatologists remain reluctant to always accept the objective numerical score and subjective “expert opinion” or “clinical diagnosis” continues to often guide treatment decisions. Well-designed research in the diagnostic accuracy in SS is needed, in order to improve the diagnostic process.
    We performed an accuracy study of the main items of the current SS diagnostic criteria in a sample of the public health system in Alberta, Canada We compared the performance of the two principal items in the ACR/EULAR criteria, anti-SSA and histopathology of labial minor salivary gland biopsy. Our analysis was approached using the standard ACR/EULAR criteria but also using a separate modification of the ACR/EULAR criteria, the latter incorporating a consideration of the clinical diagnosis and a higher anti-SSA threshold. Our results show that anti-SSA can be the main test in SS diagnostic process, but salivary gland biopsy is useful in many cases, due to its great specificity. Nevertheless, fine adjustments in both serological and histological assessments can improve the diagnostic performance of both items observed in the SS ACR/EULAR criteria.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.