Jiyoon Choi1, Kimberly Hofer2, Nishu Gaind2, Mir Sohail Fazeli2, Robert Carroll3, Antoine G Sreih3 and Antonia Christodoulou3, 1Bristol Myers Squibb, Lawrenceville, NJ, 2Evidinno Outcomes Research Inc., Vancouver, BC, Canada, 3Bristol Myers Squibb, Princeton Pike, NJ
Background/Purpose: Sjögren's syndrome (SjS) is a chronic autoimmune disease that has been historically categorized into primary (manifesting alone; pSjS) or secondary (appearing alongside another underlying autoimmune condition; sSjS) disease. Recent work has criticized this dichotomy, and instead recommends that SjS be described as a singular disease, with or without comorbidity. Previous literature reviews on the prevalence and incidence of SjS have shown varied estimates and focused on pSjS only. Epidemiological studies on overall SjS are needed to estimate the burden of illness on patients and society. We conducted a systematic literature review to describe prevalence and incidence rates of SjS, with specific focus on key countries, and to investigate geographic variations.
Methods: We searched Embase and MEDLINE® from database inception to 09/27/2022 using predefined search strategies. Gray literature searches were also conducted. Included were studies reporting prevalence or incidence rates of adults with SjS within the United States (US), EU5 (France, Germany, Italy, Spain, and the United Kingdom), China, and Japan.
Results: Of 7,121 abstracts identified from the literature searches, we included 19 studies that reported prevalence of SjS cases within a population, incidence of new cases, or both (Figure 1). We identified various designs: 10 studies were cross-sectional, 7 were retrospective cohort studies, and 2 were prospective cohort studies. Sample size ranged from 341 to 7.2 million participants (median: 25,885 participants). Baseline patient characteristics as well as the population in which prevalence or incidence were measured varied across studies; however, all study samples primarily consisted of female patients, which aligns with the real-world prevalence of SjS.
Prevalence of SjS among the general population (cases per 100,000 persons), reported in 16 studies (table 1), ranged from 13.1 to 103 in the US, from 10.2 to 3300 in Europe, and from 338.8 to 774.4 in Asia. Notably, the upper bound of the European range was from a dated survey with a small sample size; the next highest value was 748.8 cases per 100,000 persons. Prevalence was also calculated among populations with autoimmune disease such as rheumatoid arthritis (29,998 cases per 100,000 persons), systemic lupus (20,341), and multiple sclerosis (up to 12,174); these figures are much higher than those within the general population. Incidence of SjS was reported in 6 studies (Table 2). Annual incidence rates of pSjS ranged from 3.2 to 5.8 cases per 100,000 person-years within the US, and 0.1 to 4.1 cases per 100,000 person-years in France. Prevalence and incidence data for sSjS were scarce.
Conclusion: Global incidence of SjS ranges from 0.1 to 5.8 cases per 100,000 person-years and prevalence of SjS in the general population ranges from 10.2 to 3300 cases per 100,000 persons. Some of the variations may be related to, in part, the difficulty in diagnosing SjS. Prevalence rates are higher among patients with other autoimmune diseases. Large cohort studies on the prevalence and incidence of SjS alone and SjS associated with other autoimmune diseases are warranted, in particular those that look at treated versus untreated patients.
Figure 1: PRISMA flow diagram
Table 1: Prevalence rates of Sjögren’s syndrome across included studies
Table 2: Incidence rates of Sjögren’s syndrome across included studies
J. Choi: Bristol Myers Squibb, 3; K. Hofer: None; N. Gaind: None; M. Fazeli: None; R. Carroll: Bristol Myers Squibb, 3; A. Sreih: Bristol Myers Squibb, 3; A. Christodoulou: Bristol Myers Squibb, 3.