Epidemiology of Sjogren syndrome in Africa: A scoping review

Methodology

We report the review in accordance with O’Malley and Arksey methods. We searched for studies reporting on the epidemiology of Sjogren’s syndrome (SS) in Africa that were published prior to 17 May 2020, both in electronic databases (MEDLINE, EMBASE and African Journals Online) and manually. Studies which focused on Sjogren’s syndrome symptoms, reports based on fewer than 10 participants, articles not reporting primary data, and reports on multi-ethnic groups which did not allow for data specific to the African population to be extracted, were excluded. The risk of bias of each included study was assessed using Hoy et al’s criteria.

21 out of a total of 443 articles were included in our review. The studies were conducted in eight countries (Tunisia, Morocco, Egypt, Senegal, Burkina Faso, Nigeria, Tanzania and Gabon) between 1996 and 2019, and came from Northern (n = 15), Western (n = 4), Central (n = 1) and Eastern (n = 1) regions.

Data

These studies reported 744 cases of SS: 218 with primary SS (pSS), 466 with secondary SS (sSS), and 60 with unidentified subtypes. Females represented 83.3% to 100% of patients, and the mean age at diagnosis ranged from 28 to 73.6 years. Associated autoimmune diseases were rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and autoimmune hepatitis. There was no population-based incidence or prevalence. Among people with autoimmune and other rheumatic conditions, the frequency of primary SS was in the range 1.9%-47.6%, while that of rheumatoid arthritis-associated secondary SS was in the range 4.3%-100%. Sicca symptoms were the most common features, with the most frequently involved organs being joints, lungs and neurological structures. Main autoantibodies were anti-Ro/Sjögren’s syndrome antigen A, anti-La/Sjögren’s syndrome antigen B and antinuclear antibodies. Data on pharmacological treatments, quality of life and outcomes of pregnancy in women with SS are scant.

Conclusion

In conclusion, current data suggest that the epidemiology of SS in Africa is similar to that in other regions. There is an urgent need of high-quality data.