Megan R. W. Barber, Cristina Drenkard, Titilola Falasinnu, Alberta Hoi, Anselm Mak, Nien Yee Kow, Elisabet Svenungsson, Jonna Peterson, Ann E. Clarke and Rosalind Ramsey-Goldman (2021). Global epidemiology of systemic lupus erythematosus. Nature Reviews Rheumatology, 17(9), 515-532.
In a review article published in Nature Reviews | Rheumatology in 2021, the authors summarize that:
Systemic lupus erythematosus (SLE) is an autoimmune disease with protean manifestations that predominantly affects young women. Certain ethnic groups are more vulnerable than others to developing SLE and experience increased morbidity and mortality.
Reports of the global incidence and prevalence of SLE vary widely, owing to inherent variation in population demographics, environmental exposures and socioeconomic factors. Differences in study design and case definitions also contribute to inconsistent reporting. Very little is known about the incidence of SLE in Africa and Australasia. Identifying and remediating such gaps in epidemiology is critical to understanding the global burden of SLE and improving patient outcomes. Mortality from SLE is still two to three times higher than that of the general population. Internationally, the frequent causes of death for patients with SLE include infection and cardiovascular disease. Even without new therapies, mortality can potentially be mitigated with enhanced quality of care.
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Epidemiological studies in North America from the past 5 years have reinforced the concept that SLE disproportionately affects women, and racial and ethnic minorities. CDC-funded registries have provided robust data and generally report slightly higher incidence and prevalence rates than previous studies, probably because of more detailed case findings and
adjustments for case under-ascertainment. The effect of increased lifetime expectancy on an apparent rise in prevalence cannot be excluded either. Infection and cardiovascular disease are consistently top causes of death.
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... the epidemiological coverage of SLE in Europe is incomplete, with many studies
from the UK, several studies from southern Europe and Scandinavia, but few studies from central Europe and eastern Europe. The incidence and prevalence of SLE varies considerably between different European countries; however, because of the different health-care systems and methodologies used, reliable comparisons are not possible. Mortality rates are more consistent across Europe, commonly being about twice that of the general population. Cardiovascular disease and infection are major causes of mortality, together accounting for the increased mortality rate of patients with SLE compared with the general population, whereas malignancies cause proportionally fewer fatalities than in the general population. Standardized mortality rates are higher for patients with high damage scores and those patients with a younger disease onset, nephritis and/or high cumulative doses of glucocorticoids.
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Only a handful of studies have been conducted investigating the incidence and prevalence of SLE and the mortality among patients with SLE in South American countries. Because of the scarcity of resources to conduct large-scale population-based surveillance, South American studies rely on administrative data or sampling methodologies to find patients, making it difficult to compare estimates with some studies from other parts of the world. Despite these limitations, epidemiological data from South America highlight that SLE begins at a very young age among women, with the incidence peaking in women in their 20s and 30s. Similarly, although the survival of individuals with SLE in Brazil might have improved in the 2000s, the average age of mortality is still very young. Data from these epidemiological studies are fundamental to advance the understanding of health disparities in the burden of SLE and inform resource allocation in specific regions.
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Serious organ manifestations of SLE, renal disease in particular, remain prevalent in the Asia Pacific region. More work is needed to elucidate the pathophysiology of renal disease in SLE before more effective and targeted disease monitoring and therapy can be implemented. The aggressive nature and poor outcome of renal disease in Asian patients with SLE underscores the urgent need for more efficacious and less toxic regimens.
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There have not been many studies exploring the epidemiology of SLE in Australasia. Most studies explored the ethnic difference between the indigenous and white populations, demonstrating an increased prevalence of disease in the indigenous groups. With the changing landscape of demographics in the region, updated studies inclusive of other ethnicities will help to fill the knowledge gap. Furthermore, there has only been one study examining the incidence of SLE in Australia, taking observation from populations living in the Top End of the Northern Territory. The lack of large-scale population-based longitudinal studies has meant that the prevalence and incidence rates may not be reflective of the broader Australasian cities. Most existing studies also relied on relatively dated classification criteria. With the availability of revised classification criteria that have better sensitivity and specificity, future studies to explore longitudinal outcomes such as incidence rates and mortality may find a change in the epidemiology of the disease in the region.
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Emerging evidence suggests that the burden of disease and natural history of SLE in Africa might be similar to trends identified in patients of African ancestry in other settings. A few considerations unique to this region have also emerged. A sustained investment in SLE
research in Africa is needed, as well as capacity building by international rheumatology organizations, including collaborations with programmes such as the Human Heredity and Health in Africa (H3Africa) consortium, funded by the NIH and Wellcome Trust. H3Africa
seeks to apply genomic science to understand genetic and environmental contributions to the risk of chronic disease in Africa. Leveraging H3Africa for SLE research would propel the understanding of SLE risk and its clinical course. Another consideration is that the burden of infections in the general population of Africa is high. Co-infection with bacteria (such as those linked with tuberculosis) and/or viruses (such as the human immunodeficiency virus and those linked with hepatitis) can complicate the management of SLE, particularly in the choice of treatment regimens that could potentially reactivate dormant infections. Although these conditions are of relatively low prevalence in developed countries, longitudinal studies on the course of these infections in patients with SLE in Africa are warranted.
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The overall global incidence of SLE ranges between 1.5 and 11 per 100,000 person-years, and the global prevalence ranges from 13 to 7,713.5 per 100,000 individuals. This striking variation in the reported burden of SLE is in part due to inherent differences in
population structure such as sex distribution, ethnicity and environmental exposures. However, reporting bias, study design, case definition and SLE classification criteria also affect estimates of the incidence and prevalence, and variability can be high even within the same region. Women are consistently more affected by SLE than men across international regions. Black, Hispanic and Asian populations are disproportionately affected
by SLE, with higher incidence and prevalence rates in these populations than in white populations. Several studies from North America, Europe and Asia show a gradual increase in SLE prevalence over time, perhaps owing to increased recognition of the disease. Mortality among patients with SLE is still unacceptably high, being two to three times higher than that of the general population. The most consistent causes of death internationally include infection and cardiovascular disease, which can probably be mitigated through improved quality of care. Population-based studies in the developing world are urgently needed to understand the global burden of disease, potentially preventable outcomes
and to what the extent lack of specialized health-care providers, diagnostic tests and therapeutics affect SLE diagnosis and care.
Key points
The estimated incidence, prevalence and mortality of systemic lupus erythematosus (SLE) vary considerably between geographic regions.
Factors that contribute to the variation across different regions include differences in ethnicity, environmental exposures and socioeconomic status but non-uniform SLE definitions and study design also contribute.
Population-based studies in the developing world are urgently needed to understand the global burden of disease.
Mortality in patients with SLE is still unacceptably high, being two to three times higher than that of the general population.
Infectious diseases and cardiovascular disease are consistently top causes of death in patients with SLE.
Even without the development of new therapies, SLE outcomes may be improved by focusing on remediable SLE-specific adverse conditions.
Reference:
Megan R. W. Barber, Cristina Drenkard, Titilola Falasinnu, Alberta Hoi, Anselm Mak, Nien Yee Kow, Elisabet Svenungsson, Jonna Peterson, Ann E. Clarke and Rosalind Ramsey-Goldman (2021). Global epidemiology of systemic lupus erythematosus. Nature Reviews Rheumatology, 17(9), 515-532.
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