Neuromyelitis Optica Spectrum Disorders in Africa: A Systematic Review

Abstract

Background and objectives: Neuromyelitis optica (NMO) is a CNS inflammatory disease that predominantly affects the optic nerves and the spinal cord. It is more frequent in Asian and African populations than in European ones. Data on epidemiology, clinical presentation, additional investigations, and treatment in the African continent are scarce. We aim to (1) collect and analyze published data on neuromyelitis optica spectrum disorder (NMOSD), (2) indicate challenges in the diagnosis and management, and (3) discuss opportunities for future research, education, and policy making, specifically on the African continent.

Methods: A systematic review was performed in January 2021 with the search terms "Neuromyelitis optica and Africa," "Devic Disease and Africa," and "NMOSD and Africa." We included all study types except case reports, correspondence, or conference abstracts on NMO or NMOSD. Extracted data included study design, country, study period, demographic and clinical characteristics, results of paraclinical investigations, and outcome. Data analysis was performed with descriptive statistics.

Results: We retrieved a total of 79 records, of which 19 were included. Ten of 54 African countries reported a total of 410 cases. Almost half of them were from North African countries. The mean age at diagnosis was 33 years (range 7-88 years), and 75% were female. Transverse myelitis followed by optic neuritis were the most frequent symptoms at the time of presentation. One hundred nineteen patients experienced at least 1 previous relapse, and 106 had a relapsing course after diagnosis. Relapses were treated with IV methylprednisolone. Azathioprine and steroids were used most often as maintenance treatments. Outcomes were rarely described.

Discussion: The majority of studies on NMOSD from the African continent are retrospective, and most countries do not report any data. Our systemic review shows that data derived from patients living in Africa correspond well to what has been previously published in meta-analyses on patients of African ancestry with NMOSD who live outside of Africa, except for a younger age at onset and a lower proportion of females. We advocate for systematic data collection to adequately capture and monitor the burden of NMOSD, for expansion of research efforts and facilities to perform fundamental and clinical research, and for improved access to health care including diagnostics, treatments, and rehabilitation services for people affected by NMOSD in the African continent.

Figure. PRISMA Flow Diagram of the Study Selection Process