Epidemiology of Sjögren's: A Systematic Literature Review.

Introduction: Primary Sjögren's is a multi-system autoimmune disease affecting patients' physical, mental, and emotional wellbeing. The epidemiology of Sjögren's is not well understood, and up-to-date epidemiological evidence is needed to improve knowledge and awareness of Sjögren's among patients and healthcare professionals, and to ascertain the global burden of disease. The objective of this research was to conduct a de novo systematic literature review (SLR) to identify and synthesise evidence on global epidemiology of primary Sjögren's.

Methods: This SLR was conducted in May 2021 by searching MEDLINE and Embase databases, relevant conference proceedings, websites of registries, and health technology assessment agencies and databases. Publications were systematically screened for English language articles reporting on the incidence, prevalence, age at symptom onset, and age at diagnosis for people with primary Sjögren's.

Results: Of 3510 records identified, 68 publications were included, representing 62 unique studies. Studies reported on age at symptom onset (16/62; 25.8%) and age at diagnosis (43/62; 69.4%) more frequently than incidence (7/62; 11.3%) and prevalence (9/62; 14.5%). Primary Sjögren's was found to have the highest incidence and prevalence in females and in older age groups (incidence: ≥65 years; prevalence: ≥75 years). Average age at onset and diagnosis of primary Sjögren's ranged between 34-57 years and 40-67 years, respectively.

Conclusions: This SLR identified a paucity of incidence and prevalence data for primary Sjögren's, highlighting a need for further epidemiological studies. The global Sjögren's community must work together to follow the defined classification criteria of primary Sjögren's and reporting guidelines for incidence and prevalence data to allow for meaningful epidemiological comparisons across studies, settings, and countries.