The worldwide incidence and prevalence of systemic lupus erythematosus: a systematic review of epidemiological studies.

Objectives: The aim was to review the worldwide incidence and prevalence of SLE and variation with age, sex, ethnicity and time.

Methods: A systematic search of MEDLINE and EMBASE search engines was carried out using Medical Subject Headings and keyword search terms for Systemic Lupus Erythematosus combined with incidence, prevalence and epidemiology in August 2013 and updated in September 2016. Author, journal, year of publication, country, region, case-finding method, study period, number of incident or prevalent cases, incidence (per 100 000 person-years) or prevalence (per 100 000 persons) and age, sex or ethnic group-specific incidence or prevalence were collected.

Results: The highest estimates of incidence and prevalence of SLE were in North America [23.2/100 000 person-years (95% CI: 23.4, 24.0) and 241/100 000 people (95% CI: 130, 352), respectively]. The lowest incidences of SLE were reported in Africa and Ukraine (0.3/100 000 person-years), and the lowest prevalence was in Northern Australia (0 cases in a sample of 847 people). Women were more frequently affected than men for every age and ethnic group. Incidence peaked in middle adulthood and occurred later for men. People of Black ethnicity had the highest incidence and prevalence of SLE, whereas those with White ethnicity had the lowest incidence and prevalence. There appeared to be an increasing trend of SLE prevalence with time.

Conclusion: There are worldwide differences in the incidence and prevalence of SLE that vary with sex, age, ethnicity and time. Further study of genetic and environmental risk factors may explain the reasons for these differences. More epidemiological studies in Africa are warranted.