Albertino Damasceno
Universidade Eduardo Mondlane, Maputo, Mozambique
Noncommunicable diseases are new phenomena in the disease pattern of African countries. Their appearance in most African countries is recent, but their relative burden is different, undoubtedly due to the diverse economic profiles of those countries and their relative phases of epidemiologic transition [1–3]. Both stroke and ACS are increasing in frequency. Nevertheless, if we could synthesize the phenomena for the African continent we would say that the major cause of vascular end organ damage seen in sub-Saharan Africa is still precipitated by highly preventable strokes. In contrast, ACSs are an increasing but still infrequent clinical phenomenon in this setting. Specifically speaking about stroke, an important issue was highlighted in a recent paper analyzing the global burden of stroke worldwide [4]. Not only is stroke incidence increasing in LMIC (while decreasing in high-income countries), but this incidence rate has also exceeded by 20% the equivalent rates observed in high-income countries [4]. Another recently published paper reported on the first population survey of the incidence of stroke in Africa [5]. Undertaken in Tanzania, this seminal study revealed that the incidence of stroke in Dar es Salaam far exceeds the rate observed in the black African population of Manhattan, which in turn is double the incidence of the white population in the same place [5]. These two papers highlight the enormous burden of stroke in Africa and the need to build both research and clinical capacity to tackle the individual and societal consequences that burden engenders. Looking to the clinical characteristics of stroke in Africa, the two most important aspects are the younger age of incidence and the higher prevalence of the most devastating of stroke events—hemorrhagic episodes [6]. Most African studies show that stroke events occur 10 years before their onset in high-income countries. Accordingly, a large percentage of de novo strokes occur before the age of 45 years in those of African ancestry – the equivalent, negative impact on individual and societal productivity and wealth potential being that much more profound than in high-income countries. In simple terms, this means that in Africa, stroke kills and disables people in the active phase of life, exacerbating the economic burden of already poor families. The other important factor is the high prevalence of hemorrhagic strokes. While in most high-income countries hemorrhagic stroke accounts for less than 10% of stroke cases, in several African studies this proportion was as high as 40% [7]. These two characteristics reflect the phenomenon of epidemiologic transition currently underway in most African countries.
As described in Section 3, hypertension is extremely prevalent and poorly controlled in most sub-Saharan African countries; the affected population is young, and diabetes and dyslipidemia, although increasing, remain less frequent than in high-income countries [8]. As will be described in Chapter 13, cases of hypertensive HF are likely to rise. However, stroke is already a major consequence of uncontrolled hypertension across the continent. Hemorrhagic stroke carries a higher mortality rate than its ischemic counterpart, and stroke patients in Africa are admitted to general wards where basic but specific treatments of the acute phase simply do not exist. These are probably the two most crucial contributors to the high mortality rate of stroke in Africa.
On this basis, this section presents two streams of research in this context. Chapter 10 presents a body of research focusing on the prevalence and characteristics of ACS in those captured by the Heart of Soweto Study and subjected to more intensive clinical and basic research profiling. In contrast, Chapter 11 summarizes the results of a population study of stroke in the city of Maputo, Mozambique. Both research programs, in addition to the key publications highlighted above, have been instrumental in highlighting the evolving issue of stroke and ACS from a uniquely African context.
Section 5 of this book begins in Chapter 10 with the South African subset of an international multicenter registry before moving to two studies based in Soweto (for profiles of Soweto and South Africa, see Section 1). Chapter 11 shifts to the southeastern section of the continent, highlighting the Mozambican capital city of Maputo (for an introduction to Mozambique, refer to Section 2).
Maputo is the capital, largest city, and administrative hub of Mozambique. With a population of approximately 1.87 million individuals, Maputo is home to 56 ethnic groups and many associated native languages, while Portuguese is the official language [9]. Due to rapid expansion, the city is facing increased pressure on critical infrastructure, and around three-quarters of the population are housed in informal or unplanned settlements in suboptimal environmental conditions, with associated negative health implications [10]. Health systems and other basic public services are also overburdened, and high unemployment and food insecurity are continuing concerns [11,12]. However, levels of literacy and educational attainment are reported to be higher in Maputo than in neighbouring areas, although this is subject to notable gender inequality, which also affects health education and access to health care [13]. Average life expectancy in Maputo is 57 years [14,15], and close to 20% of residents aged 15 or above are infected with HIV/AIDS [16]. However, rates of infant and child mortality in the city are lower than reported in other parts of Mozambique [17].