Author: Anna Gardin

Stroke Unit, Clinical and Experimental Medicine Department, University Hospital “G. Martino”, Messina, Italy

Twitter: @AnnaGardin1

Globally, stroke is one of the leading causes of death and chronic disability. About 70% of all stroke deaths and 87% of stroke-related disability cases occur in low- and middle-income countries (LMICs), including the majority of Sub-Saharan Africa (SSA).[1] Analysing the data of the Global Burden Disease study, the worldwide incidence and mortality of stroke are likely to decrease, but the area of SSA has demonstrated an increasing trend.[2]

The most common cause of ischemic stroke in SSA is cerebral small vessel disease (CSVD) (42%), followed by large vessel atherosclerotic disease (17%), cardioembolism (11%), and an undetermined cause (30%).[1] The burden of CSVD may be explained by the effect of undiagnosed and uncontrolled risk factors (e.g. hypertension, dyslipidemia, or hyperglycemia), which can favour the arteriolosclerotic process of deep perforating arteries.[1]

Within the group of strokes due to other determined causes, haematologic disorders represent a relevant part, especially in SSA, where a high incidence of sickle cell disease (SCD) exists.[4] This pathology is responsible for a certain percentage of stroke cases in both pediatric and adult populations. According to the American Society of Hematology (ASH) guidelines for SCD, annual transcranial Doppler ultrasound (TCD) monitoring is recommended as a well-established primary stroke prevention strategy.[3] Considering the time-averaged mean of the maximum velocity of a non-imaging TCD, two measurements >200 cm/s or a single measurement >220 cm/s in the distal internal carotid artery or proximal middle cerebral artery is associated with a greater risk of stroke. That risk can be lowered by regular monthly blood transfusions for at least 1 year.[3]

However, access to stroke care in SSA is often limited, and a large part of these populations can’t afford the stroke care that is available and recommended by the international guidelines[1], including, for example, blood transfusion therapy or chelation therapy for SCD. Behind this background, countries such as Nigeria, Uganda, Angola, and the Democratic Republic of Congo aimed at developing and testing alternative therapy options that might be accessible to a large part of the affected population. In several clinical studies, they successfully demonstrated that hydroxyurea therapy is effective and safe for children with SCD and abnormal TCD measurements.[4-8] Consequently, this alternative option has been included in the 2020 ASH guidelines.[3]

In summary, the majority of stroke cases in the world occur in LMICs, but, at the same time, these patients are often underrepresented in the principal international trials, which recommend interventions that are not always affordable for all.[9] The above-mentioned African studies represent a brilliant example of the great utility of data from SSA, considering the limited resources of these areas, and suggesting widely affordable strategies as an effective therapy. Nowadays, the real challenge for researchers should be proposing new diagnostic, therapeutic, and prevention options, from which everyone can benefit, regardless of their economic level. This could effectively help improve stroke assistance worldwide, allowing as many people as possible to receive the best evidence-based stroke care.


1. Akinyemi RO, Ovbiagele B, Adeniji OA, Sarfo FS, Abd-Allah F, Adoukonou T, Ogah OS, Naidoo P, Damasceno A, Walker RW, Ogunniyi A, Kalaria RN, Owolabi MO. Stroke in Africa: profile, progress, prospects and priorities. Nat Rev Neurol. 2021 Oct;17(10):634-656. doi: 10.1038/s41582-021-00542-4. Epub 2021 Sep 15. PMID: 34526674; PMCID: PMC8441961.

2. Adoukonou T, Kossi O, Fotso Mefo P, Agbétou M, Magne J, Gbaguidi G, Houinato D, Preux PM, Lacroix P. Stroke case fatality in sub-Saharan Africa: Systematic review and meta-analysis. Int J Stroke. 2021 Oct;16(8):902-916. doi: 10.1177/1747493021990945. Epub 2021 Feb 2. PMID: 33527885.

3. DeBaun MR, Jordan LC, King AA, Schatz J, Vichinsky E, Fox CK, McKinstry RC, Telfer P, Kraut MA, Daraz L, Kirkham FJ, Murad MH. American Society of Hematology 2020 guidelines for sickle cell disease: prevention, diagnosis, and treatment of cerebrovascular disease in children and adults. Blood Adv. 2020 Apr 28;4(8):1554-1588. doi: 10.1182/bloodadvances.2019001142. PMID: 32298430; PMCID: PMC7189278.

4. Tshilolo L, Tomlinson G, Williams TN, Santos B, Olupot-Olupot P, Lane A, Aygun B, Stuber SE, Latham TS, McGann PT, Ware RE; REACH Investigators. Hydroxyurea for Children with Sickle Cell Anemia in Sub-Saharan Africa. N Engl J Med. 2019 Jan 10;380(2):121-131. doi: 10.1056/NEJMoa1813598. Epub 2018 Dec 1. PMID: 30501550; PMCID: PMC6454575.

5. Opoka RO, Ndugwa CM, Latham TS, Lane A, Hume HA, Kasirye P, Hodges JS, Ware RE, John CC. Novel use Of Hydroxyurea in an African Region with Malaria (NOHARM): a trial for children with sickle cell anemia. Blood. 2017 Dec 14;130(24):2585-2593. doi: 10.1182/blood-2017-06-788935. Epub 2017 Oct 19. PMID: 29051184.

6. Galadanci NA, Abdullahi SU, Ali Abubakar S, Wudil Jibir B, Aminu H, Tijjani A, Abba MS, Tabari MA, Galadanci A, Borodo AM, Belonwu R, Salihu AS, Rodeghier M, Ghafuri DL, Covert C Greene BV, Neville K, Kassim AA, Kirkham FJ, Jordan LC, Aliyu MH, DeBaun MR. Moderate fixed-dose hydroxyurea for primary prevention of strokes in Nigerian children with sickle cell disease: Final results of the SPIN trial. Am J Hematol. 2020 Sep;95(9):E247-E250. doi: 10.1002/ajh.25900. Epub 2020 Jul 10. PMID: 32510680; PMCID: PMC8697367.

7. Abdullahi SU, Jibir BW, Bello-Manga H, Gambo S, Inuwa H, Tijjani AG, Idris N, Galadanci A, Hikima MS, Galadanci N, Borodo A, Tabari AM, Haliru L, Suleiman A, Ibrahim J, Greene BC, Ghafuri DL, Rodeghier M, Slaughter JC, Kirkham FJ, Neville K, Kassim A, Trevathan E, Jordan LC, Aliyu MH, DeBaun MR. Hydroxyurea for primary stroke prevention in children with sickle cell anaemia in Nigeria (SPRING): a double-blind, multicentre, randomised, phase 3 trial. Lancet Haematol. 2022 Jan;9(1):e26-e37. doi: 10.1016/S2352-3026(21)00368-9. PMID: 34971579; PMCID: PMC10072240.

8. Lagunju I, Brown BJ, Oyinlade AO, Asinobi A, Ibeh J, Esione A, Sodeinde OO. Annual stroke incidence in Nigerian children with sickle cell disease and elevated TCD velocities treated with hydroxyurea. Pediatr Blood Cancer. 2019 Mar;66(3):e27252. doi: 10.1002/pbc.27252. Epub 2018 May 24. PMID: 29797633.

9. Opare-Addo PA, Sarfo FS, Berchie PO, Aikins M, Ovbiagele B. Participation by patients from low- and middle-income countries (LMICs) in trial evidence supporting secondary stroke prevention guideline recommendations. J Neurol Sci. 2023 May 15;448:120641. doi: 10.1016/j.jns.2023.120641. Epub 2023 Mar 31. PMID: 37028264.

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