Systemic lupus erythematosus in Native sub-Saharan Africans: A systematic review and meta-analysis

Background: The prevalence and phenotype of systemic lupus erythematosus (SLE) have not been thoroughly investigated in Native sub-Saharan Africans despite knowledge that the highest burden of SLE occurs in people with an African trait. Through this systematic review of literature and meta-analysis, we wished to fill this gap. Methods: PubMed, EMBASE, Web of Science, African Journals Online, and Global Index Medicus as well as references of retrieved papers were searched to select studies addressing SLE in Native sub-Saharan Africans and published between January 1, 2008 and October 7, 2018. The prevalence of SLE and its characteristics were pooled through narrative review and random-effects model. Heterogeneity (I-2) was assessed via the chi(2) test. Pooled estimates are expressed with 95% confidence intervals. This study is registered with PROSPERO: registration number CRD42019139226. Results: Out of 1502 papers, 15 hospital-based studies were included. The pooled prevalence of SLE among 28,575 participants was 1.7% (0.8-2.9), with substantial heterogeneity between studies (I-2 = 96.9% [94.8%; 98.1%], tau 2 = 0.0020, p < 0.0001). The mean age at diagnosis ranged from 28.8 to 39.2 years. The female proportion varied from 88% to 100%. Rheumatological (5.1%-99.9%), dermatological (4.3%-100%) and hematological (1.4-86.9%) manifestations were the commonest clinical features of SLE. Patients had a high - seroprevalence for anti-ribonucleoprotein 57.9% (36.4-77.9), anti-Smith 53.5% (40.4-66.2), anti-Sjogren syndrome antigen A 45.6% (19.2-73.4) and anti-Sjogren syndrome antigen B 33.7% (13.6-57.6) autoantibodies. The most used treatments were corticosteroids 99% (94.9-100) and antimalarials 62. 8% (23.3-94.1). The pooled mortality rate was 10.3% (3.3-20.6) and death was mainly due to infections, kidney disease and neurological involvement. Conclusion: Over the last 30 years, SLE was not rare among Native sub-Saharan Africans and its featured characteristics were earlier onset, female predominance, and high seropositivity for extractable nuclear antigen autoantibodies. Corticosteroids and antimalarials were the standard treatments. The mortality rate was high. Population prevalence and incidence as well as full description of SLE characteristics in Native sub-Saharan Africans are needed.