| Prevalence |
| 18 studies Databases searched: PubMed and EMBASE Updated search on 22 October 2013. Inclusion criteria: ‘Population-based studies and surveys examining a geographic region or clearly defined random or clustered sampling procedure’. Exclusion criteria: Hospital or clinic reports including survey or audits.
| Systematic review 21 overall systematic reviews (15 reported prevalence and incidence in the EU, 2 in America, and 4 in Asia) Subgroup analyses by case definitions. Performed a meta-analysis with random effects model to pool data.
| Overall prevalence: 60.82 (43.69–77.94) per 100 000. Female: 116.72 (70.39–163.05). Male: 5.53 (2.49–8.58) 11 studies from Europe pooled prevalence rate: 71.22 (95% CI 48.7, 93.7) per 100 000. Studies from Asia 44.85 (3.51–86.2) I2 = 98.95
| | High quality |
Albrecht et al. (2023) [14] Programme Area Epidemiology and Health Services Research, German Rheumatism Research Centre Berlin, Germany
| 20 studies Databases searched: PubMed and Web of Science Search period (2014–8 November 2022). Inclusion criteria: German or English language. Prevalence of inflammatory rheumatic disease (i.e. connective tissue diseases) Adults or children and adolescents in Germany were included.
| Systematic review a narrative synthesis was reported. Individuals in Germany with inflammatory Rheumatic Diseases. Did not perform a meta-analysis
| 680–770 cases per 100 000 population from 2007 to 2018. German prevalence, 40 cases per 100 000 assumed so far. SS including sicca syndrome 70–770 cases per 100 000. Primary Sjögren’s—70 per 100 000. Global prevalence 60.8 (95% CI 43.7, 77.9/100 000)
| All studies have a moderate to high risk of bias | Acceptable |
| Incidence |
| | Systematic review Six studies describing incidence rates for primary SS. Three from Taiwan, two from Europe. One from the USA. Performed a meta-analysis with random effects model to pool data.
| Pooled estimate Pooled incidence rate: 6.92 (95% CI 4.98, 8.86) per 100 000. Female: 12.30 (9.07–15.53) Male: 1.47 (0.81–2.12) Female/Male: 9.29 (6.61–13.04). Studies from Asia reported an incidence rate ranging from 6.0 to 11.8 per 100 000. EU ranges from 3.9 to 5.3 per 100 000 person-years. USA prospective population-based study 1976–1992 reported an incidence rate of 3.9 per 100 000 person-years. I2=98.51
| | High quality |
| Mortality |
Singh et al. (2016) [4] Division of Rheumatology and Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA
| 10 studies Databases searched: Ovid Medline In-Process, OVID EMBASE Search: each databases inception to 27 October 2014. Inclusion criteria: ‘Population-based or representative of the community rheumatology practice or multicentre studies. Mortality rate in primary Sjögren’s patients (with or without risk factors and causes of mortality) and compared the mortality rate with the general population or matched control population, reported as SMR or RR, respectively’. Exclusion criteria: ‘single-centre studies with high attrition rate (<80% follow-up); lack of comparison of mortality rate to a control, non-SS population; and studies with insufficient information to allow estimation of SMR with 95% CI’
| Systematic review Cohort studies of primary SS patients. Population based rheumatology practice or multicentre studies. Mortality rate vs general population. In total, 7888 patients and 682 died. Median follow-up of 9 years. 91% female. Performed a meta-analysis with random effects model to pool data.
| Pooled estimate Pooled SMR: 1.38 (95% CI 0.94, 2.01). Leading causes of death were cardiovascular diseases, solid-organ and lymphoid malignancies and infections. Unclear whether over-representation in the Sjögren’s population than general population. Subgroup analyses: Advanced age of diagnosis RR 1.09 (1.07–1.12) Male sex RR 2.18 (1.45–2.37) Vasculitis RR 7.27 (2.70, 19.57) anti-SSB positivity [RR 1.45 (95% CI 1.03, 2.04)] cryoglobulinemia [RR 2.62 (95% CI 1.77, 3.90)] Examined other risk factors parotid enlargement. Primary SS was not associated with an increase in all-cause mortality compared with the general population. I2 = 94%
| No publication bias was found. | High quality |
| Two cohort studies Databases searched: Medline and Cochrane Library. Search: up to March 2018 Inclusion criteria: systematic reviews included ‘case-control, cohort, and cross-sectional studies. Index cases age >18 years. Primary SS diagnosis based on several definitions. Control group of healthy individuals’. Exclusion criteria: ‘Patients with secondary Sjögren’s or another immune mediated inflammatory disease’.
| Systematic review Cardiovascular mortality. ‘Risk of cardiovascular mortality’ 745 subjects and 25 cardiac-related deaths. Performed a meta-analysis with random effects model to pool data.
| No statistically significant association between Primary SS and cardiovascular mortality RR 1.48 (0.77–2.85, P = 0.24). An association between cardiovascular morbidity. Control group: Yes I2 = 44%
| No publication bias was found | Acceptable |
| 14 studies Databases searched: PubMed, Cochrane Library and EMBASE—23 October 2020. Inclusion criteria: ‘Population-based, single-centre or multicentre cohort studies. The all-cause mortality rate was assessed through a comparison with the general population or a matched control group, or by directly reporting the Standardized Mortality Ratio (SMR)’.
| Systematic review All-cause mortality rate vs general population. 14 584 patients. 902 deaths observed. Performed a meta-analysis with random effects model to pool data.
| Pooled estimate Primary SS SMR 1.46-fold (95% CI 1.10, 1.93) greater than general population. Risk higher in European countries: 1.55 (1.04–2.33). Primary SS was associated with mortality in the general population. 46% increase in death. Subgroup analyses Age (per one year) RR 1.09 (1.06–1.12) Male gender RR 1.95 (1.15–3.31), I2 = 26.2 Vasculitis RR 7.27 (2.70–19.57) Anti-La/SS-B+ RR 1.45 (1.03–2.04) Cryoglobulinaemia RR 2.62 (1.77–3.90) I2 = 92.4%
| No publication bias was found | High quality |
