Noncommunicable Diseases in Sub-Saharan Africa: Where Do They Feature in the Health Research Agenda? (Theme Papers)

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Voir page 952 le resume en francais. En la pagina 952 figura un resumen en espanol.

Noncommunicable diseases in sub-Saharan Africa: not a priority?

At present, conventional wisdom states that noncommunicable diseases are not a high priority, area for health research and development in the countries of sub-Saharan Africa. The estimates in the 1990 Global Burden of Disease study suggested that noncommunicable diseases accounted for only 14% of the total burden in sub-Saharan Africa, and for just under a third in adults aged 15-59 years (1). Nonetheless, in absolute terms the estimates also suggested that the probability of death from noncommunicable diseases is higher in sub-Saharan Africa than in Established Market Economies. Because of the lack of reliable mortality and morbidity data from sub-Saharan Africa, these estimates are heavily based on assumptions and extrapolations (2). However, this picture of a high probability of death from noncommunicable diseases with a low contribution of these conditions to the overall burden of disease is supported by real data. Fig. 1 and Fig. 2 present age-adjusted mortality rates from the Tanzanian demographic surveillance system of the Adult Morbidity and Mortality Project (3, 4). The histogram blocks in Fig. 1 and Fig. 2 show that in at least three areas of United Republic of Tanzania, one of Africa's poorest countries, the probabilities of death from noncommunicable diseases are indeed higher than in Established Market Economies. Additionally, among adults, the age-specific death rates from noncommunicable diseases are substantially higher in all age groups (i.e. 15-29 years, 30-44 years, and 45-59 years) in these three areas of the country than in the Established Market Economies. On the other hand, noncommunicable diseases account for 15-25% of all adult deaths (i.e. in persons aged 15-59 years) in the Tanzanian areas covered by the demographic surveillance system, a much smaller proportion than the 67% (men) to 80% (women) in the Established Market Economies.

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Using data from the Global Burden of Disease study, Gwatkin et al. have argued that, irrespective of the high absolute death rates from noncommunicable diseases, to increase the priority given to them (and thus lower the priority, accorded to communicable diseases, given the limited resources) would work to the disadvantage of the world's poorest 20%, a quarter of whom live in sub-Saharan Africa (5). This conclusion and its basis have been criticized for several reasons. These include the validity of comparing noncommunicable diseases, which are strongly age related, between populations with very different age structures and life expectancy; and the fact that these analyses were based on the richest and poorest 20% of the world's population, when most of the intervening 60% live in low- and middle-income countries (6). Nonetheless, the paper by Gwatkin et al. helped to enunciate a widely held view that shifting the priority to noncommunicable diseases in low income countries would work to the disadvantage of persons who are most in need. In addition, estimates of the cost-effectiveness of treating noncommunicable diseases are substantially lower than those for many infectious diseases. For example, out of 40 health interventions evaluated in Guinea (7) the most cost-effective treatment for a noncommunicable disease was estimated to be aspirin for preexisting heart disease, at US$ 257 per year of life saved. This was ranked 31st out of the list of 40, and contrasts with interventions such as treatment of pneumonia in children, vaccination, and short-course treatment for tuberculosis, all of which were estimated to cost less than US$ 50 per year of life saved. Similarly, even though cheap and effective drugs exist for the treatment of hypertension, and the potential benefits of its treatment in terms of avoidable mortality are likely to be greater in sub-Saharan Africa than in the Established Market Economies (8), it was ranked last out of the 40 interventions considered, at US$ 2281 per year of life saved. …